From patchwork Wed Mar 3 10:15:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 1446550 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=bwFSA/rr; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=b4AIUKig; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Dr8zQ56MCz9sTD for ; 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dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=b4AIUKig; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Dr8yd2G0lz3cQ4 for ; Wed, 3 Mar 2021 21:15:37 +1100 (AEDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1614766534; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5o9MzMrMVFlLOrKhgcDQAebO+43Y5uWT9SA1yv2Ku+g=; b=bwFSA/rrtpSQRBUFgvjdXyepSjJgb+fxucVlBOc+8jJJHB2sj6Ae9JWiYGZ92uSYBYQe51 3UmPfP0BVxpeFbz9uCkYvzRLNaoKX24SO0aMY8MQhip1AqZAAXAEc82gnyaEOm7x9yjqFO cbK55PeRX2htHvbnZZqaaSRHodmFEmlZldRSr/wh7r01k2H1aBuc+a/2xHWOPXIoLoCgbJ XZaq60bOHR0tEUrwAwnpU+/ewCewVX6Knj/Mhje4bFAtSYdWQVskamKKBEbvWK4zHw+za1 AF1ia9QLG0SLgNAsQEFOGdDlXF01GcqVjWPqtzfiHMJOsTh/YNommPga9UXSQw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1614766534; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5o9MzMrMVFlLOrKhgcDQAebO+43Y5uWT9SA1yv2Ku+g=; b=b4AIUKighv58GLWloH8f5crxzzmO16h7hplt8+zY51ZxO6SaKEWxthJ+u996O+DdnU+3Wc 4LdHTBFSjSCqHOBQ== To: Petr Mladek Subject: [PATCH next v4 11/15] printk: kmsg_dumper: remove @active field Date: Wed, 3 Mar 2021 11:15:24 +0100 Message-Id: <20210303101528.29901-12-john.ogness@linutronix.de> In-Reply-To: <20210303101528.29901-1-john.ogness@linutronix.de> References: <20210303101528.29901-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sergey Senozhatsky , Douglas Anderson , Paul Mackerras , Kees Cook , Daniel Thompson , Madhavan Srinivasan , Jordan Niethe , Wei Li , Ravi Bangoria , Pavel Tatashin , Alistair Popple , Steven Rostedt , Davidlohr Bueso , Nicholas Piggin , Oleg Nesterov , Thomas Gleixner , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Jason Wessel , kgdb-bugreport@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, Mike Rapoport Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" All 6 kmsg_dumpers do not benefit from the @active flag: (provide their own synchronization) - arch/powerpc/kernel/nvram_64.c - arch/um/kernel/kmsg_dump.c - drivers/mtd/mtdoops.c - fs/pstore/platform.c (only dump on KMSG_DUMP_PANIC, which does not require synchronization) - arch/powerpc/platforms/powernv/opal-kmsg.c - drivers/hv/vmbus_drv.c The other 2 kmsg_dump users also do not rely on @active: (hard-code @active to always be true) - arch/powerpc/xmon/xmon.c - kernel/debug/kdb/kdb_main.c Therefore, @active can be removed. Signed-off-by: John Ogness Reviewed-by: Petr Mladek --- arch/powerpc/xmon/xmon.c | 2 +- include/linux/kmsg_dump.h | 2 -- kernel/debug/kdb/kdb_main.c | 2 +- kernel/printk/printk.c | 10 +--------- 4 files changed, 3 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 3fe37495f63d..80ed3e1becf9 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3001,7 +3001,7 @@ print_address(unsigned long addr) static void dump_log_buf(void) { - struct kmsg_dumper dumper = { .active = 1 }; + struct kmsg_dumper dumper; unsigned char buf[128]; size_t len; diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 070c994ff19f..84eaa2090efa 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -36,7 +36,6 @@ enum kmsg_dump_reason { * through the record iterator * @max_reason: filter for highest reason number that should be dumped * @registered: Flag that specifies if this is already registered - * @active: Flag that specifies if this is currently dumping * @cur_seq: Points to the oldest message to dump * @next_seq: Points after the newest message to dump */ @@ -44,7 +43,6 @@ struct kmsg_dumper { struct list_head list; void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason); enum kmsg_dump_reason max_reason; - bool active; bool registered; /* private state of the kmsg iterator */ diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 930ac1b25ec7..315169d5e119 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2101,7 +2101,7 @@ static int kdb_dmesg(int argc, const char **argv) int adjust = 0; int n = 0; int skip = 0; - struct kmsg_dumper dumper = { .active = 1 }; + struct kmsg_dumper dumper; size_t len; char buf[201]; diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index e794a08de00f..ce4cc64ba7c9 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3408,8 +3408,6 @@ void kmsg_dump(enum kmsg_dump_reason reason) continue; /* initialize iterator with data about the stored records */ - dumper->active = true; - logbuf_lock_irqsave(flags); dumper->cur_seq = latched_seq_read_nolock(&clear_seq); dumper->next_seq = prb_next_seq(prb); @@ -3417,9 +3415,6 @@ void kmsg_dump(enum kmsg_dump_reason reason) /* invoke dumper which will iterate over records */ dumper->dump(dumper, reason); - - /* reset iterator */ - dumper->active = false; } rcu_read_unlock(); } @@ -3454,9 +3449,6 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, prb_rec_init_rd(&r, &info, line, size); - if (!dumper->active) - goto out; - /* Read text or count text lines? */ if (line) { if (!prb_read_valid(prb, dumper->cur_seq, &r)) @@ -3542,7 +3534,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, bool ret = false; bool time = printk_time; - if (!dumper->active || !buf || !size) + if (!buf || !size) goto out; logbuf_lock_irqsave(flags); From patchwork Wed Mar 3 10:15:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 1446551 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=jptMt/lC; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=EUpeJ9EX; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Dr8zx18YTz9sPf for ; Wed, 3 Mar 2021 21:16:45 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Dr8zx036wz3dGP for ; Wed, 3 Mar 2021 21:16:45 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=jptMt/lC; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=EUpeJ9EX; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linutronix.de (client-ip=2a0a:51c0:0:12e:550::1; helo=galois.linutronix.de; envelope-from=john.ogness@linutronix.de; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=jptMt/lC; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=EUpeJ9EX; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Dr8yf6CLFz3cXt for ; Wed, 3 Mar 2021 21:15:38 +1100 (AEDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1614766536; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=n8h6yZzQL8ZfWHLvEs3QAIVV1g9tQwJ5TiQ/YxHavlw=; b=jptMt/lCurssOvVO7r4XOpmMX3yvoEvhYlxqNQ2oDOuliPMqszhh7NPzy6MW9huUbAynA3 p3gA+SBhpgnysAbLWOnRMe3UjYt3vc3GHgcmQo850eMeVsU0l/DArr4PEUIurGPuTySCLa seb5sV/saOiAR6J+uvljNbSqEFhvgcnQnFAdAImILJAXezEjguCKRGkG229c5LxQVq2VIH 8qwXryTr9bynnAQiBx2b4Lw+Hh0FD7kYLvn8ToyAGOAP12ekpF10iXAfopTRIA7h7/7Xl6 ++4X/JmdaaJ7UuySMo/frYK8wgOb0fOrTh7BkyemdVttnWA3AfFxvX8BPBQEfQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1614766536; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=n8h6yZzQL8ZfWHLvEs3QAIVV1g9tQwJ5TiQ/YxHavlw=; b=EUpeJ9EXIltwzNOFI1QL82PS0Fqehccz1OGv20ytOLGysj/50hWuh05HY7sP6T0fOc1ZtH KNYu4MrbKwLjfZAA== To: Petr Mladek Subject: [PATCH next v4 12/15] printk: introduce a kmsg_dump iterator Date: Wed, 3 Mar 2021 11:15:25 +0100 Message-Id: <20210303101528.29901-13-john.ogness@linutronix.de> In-Reply-To: <20210303101528.29901-1-john.ogness@linutronix.de> References: <20210303101528.29901-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-hyperv@vger.kernel.org, Sergey Senozhatsky , Douglas Anderson , Paul Mackerras , Miquel Raynal , "K. Y. Srinivasan" , Thomas Meyer , Vignesh Raghavendra , Wei Liu , Madhavan Srinivasan , Stephen Hemminger , Anton Vorontsov , Jason Wessel , Anton Ivanov , Wei Li , Haiyang Zhang , Ravi Bangoria , Kees Cook , Alistair Popple , Jeff Dike , Colin Cross , linux-um@lists.infradead.org, Daniel Thompson , Steven Rostedt , Davidlohr Bueso , Nicholas Piggin , Oleg Nesterov , Thomas Gleixner , Andy Shevchenko , Jordan Niethe , Michael Kelley , Christophe Leroy , Tony Luck , Pavel Tatashin , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Richard Weinberger , kgdb-bugreport@lists.sourceforge.net, linux-mtd@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Mike Rapoport Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Rather than storing the iterator information in the registered kmsg_dumper structure, create a separate iterator structure. The kmsg_dump_iter structure can reside on the stack of the caller, thus allowing lockless use of the kmsg_dump functions. Update code that accesses the kernel logs using the kmsg_dumper structure to use the new kmsg_dump_iter structure. For kmsg_dumpers, this also means adding a call to kmsg_dump_rewind() to initialize the iterator. All this is in preparation for removal of @logbuf_lock. Signed-off-by: John Ogness Reviewed-by: Kees Cook # pstore Reviewed-by: Petr Mladek --- arch/powerpc/kernel/nvram_64.c | 8 +++-- arch/powerpc/xmon/xmon.c | 6 ++-- arch/um/kernel/kmsg_dump.c | 5 ++- drivers/hv/vmbus_drv.c | 4 ++- drivers/mtd/mtdoops.c | 5 ++- fs/pstore/platform.c | 5 ++- include/linux/kmsg_dump.h | 36 ++++++++++--------- kernel/debug/kdb/kdb_main.c | 10 +++--- kernel/printk/printk.c | 63 +++++++++++++++++----------------- 9 files changed, 80 insertions(+), 62 deletions(-) diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c index 532f22637783..3c8d9bbb51cf 100644 --- a/arch/powerpc/kernel/nvram_64.c +++ b/arch/powerpc/kernel/nvram_64.c @@ -647,6 +647,7 @@ static void oops_to_nvram(struct kmsg_dumper *dumper, { struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf; static unsigned int oops_count = 0; + static struct kmsg_dump_iter iter; static bool panicking = false; static DEFINE_SPINLOCK(lock); unsigned long flags; @@ -681,13 +682,14 @@ static void oops_to_nvram(struct kmsg_dumper *dumper, return; if (big_oops_buf) { - kmsg_dump_get_buffer(dumper, false, + kmsg_dump_rewind(&iter); + kmsg_dump_get_buffer(&iter, false, big_oops_buf, big_oops_buf_sz, &text_len); rc = zip_oops(text_len); } if (rc != 0) { - kmsg_dump_rewind(dumper); - kmsg_dump_get_buffer(dumper, false, + kmsg_dump_rewind(&iter); + kmsg_dump_get_buffer(&iter, false, oops_data, oops_data_sz, &text_len); err_type = ERR_TYPE_KERNEL_PANIC; oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION); diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 80ed3e1becf9..5978b90a885f 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3001,7 +3001,7 @@ print_address(unsigned long addr) static void dump_log_buf(void) { - struct kmsg_dumper dumper; + struct kmsg_dump_iter iter; unsigned char buf[128]; size_t len; @@ -3013,9 +3013,9 @@ dump_log_buf(void) catch_memory_errors = 1; sync(); - kmsg_dump_rewind_nolock(&dumper); + kmsg_dump_rewind_nolock(&iter); xmon_start_pagination(); - while (kmsg_dump_get_line_nolock(&dumper, false, buf, sizeof(buf), &len)) { + while (kmsg_dump_get_line_nolock(&iter, false, buf, sizeof(buf), &len)) { buf[len] = '\0'; printf("%s", buf); } diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c index a765d235e50e..0224fcb36e22 100644 --- a/arch/um/kernel/kmsg_dump.c +++ b/arch/um/kernel/kmsg_dump.c @@ -10,6 +10,7 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { + static struct kmsg_dump_iter iter; static DEFINE_SPINLOCK(lock); static char line[1024]; struct console *con; @@ -35,8 +36,10 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, if (!spin_trylock_irqsave(&lock, flags)) return; + kmsg_dump_rewind(&iter); + printf("kmsg_dump:\n"); - while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) { + while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) { line[len] = '\0'; printf("%s", line); } diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 10dce9f91216..b341b144bde8 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1391,6 +1391,7 @@ static void vmbus_isr(void) static void hv_kmsg_dump(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { + struct kmsg_dump_iter iter; size_t bytes_written; phys_addr_t panic_pa; @@ -1404,7 +1405,8 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper, * Write dump contents to the page. No need to synchronize; panic should * be single-threaded. */ - kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE, + kmsg_dump_rewind(&iter); + kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE, &bytes_written); if (bytes_written) hyperv_report_panic_msg(panic_pa, bytes_written); diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 8bbfba40a554..862c4a889234 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -277,14 +277,17 @@ static void mtdoops_do_dump(struct kmsg_dumper *dumper, { struct mtdoops_context *cxt = container_of(dumper, struct mtdoops_context, dump); + struct kmsg_dump_iter iter; /* Only dump oopses if dump_oops is set */ if (reason == KMSG_DUMP_OOPS && !dump_oops) return; + kmsg_dump_rewind(&iter); + if (test_and_set_bit(0, &cxt->oops_buf_busy)) return; - kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, + kmsg_dump_get_buffer(&iter, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, record_size - MTDOOPS_HEADER_SIZE, NULL); clear_bit(0, &cxt->oops_buf_busy); diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index d963ae7902f9..b9614db48b1d 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -385,6 +385,7 @@ void pstore_record_init(struct pstore_record *record, static void pstore_dump(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { + struct kmsg_dump_iter iter; unsigned long total = 0; const char *why; unsigned int part = 1; @@ -405,6 +406,8 @@ static void pstore_dump(struct kmsg_dumper *dumper, } } + kmsg_dump_rewind(&iter); + oopscount++; while (total < kmsg_bytes) { char *dst; @@ -435,7 +438,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, dst_size -= header_size; /* Write dump contents. */ - if (!kmsg_dump_get_buffer(dumper, true, dst + header_size, + if (!kmsg_dump_get_buffer(&iter, true, dst + header_size, dst_size, &dump_size)) break; diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 84eaa2090efa..36c8c57e1051 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -29,6 +29,16 @@ enum kmsg_dump_reason { KMSG_DUMP_MAX }; +/** + * struct kmsg_dump_iter - iterator for retrieving kernel messages + * @cur_seq: Points to the oldest message to dump + * @next_seq: Points after the newest message to dump + */ +struct kmsg_dump_iter { + u64 cur_seq; + u64 next_seq; +}; + /** * struct kmsg_dumper - kernel crash message dumper structure * @list: Entry in the dumper list (private) @@ -36,35 +46,29 @@ enum kmsg_dump_reason { * through the record iterator * @max_reason: filter for highest reason number that should be dumped * @registered: Flag that specifies if this is already registered - * @cur_seq: Points to the oldest message to dump - * @next_seq: Points after the newest message to dump */ struct kmsg_dumper { struct list_head list; void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason); enum kmsg_dump_reason max_reason; bool registered; - - /* private state of the kmsg iterator */ - u64 cur_seq; - u64 next_seq; }; #ifdef CONFIG_PRINTK void kmsg_dump(enum kmsg_dump_reason reason); -bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len); -bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len); -bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, char *buf, size_t size, size_t *len_out); -void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper); +void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter); -void kmsg_dump_rewind(struct kmsg_dumper *dumper); +void kmsg_dump_rewind(struct kmsg_dump_iter *iter); int kmsg_dump_register(struct kmsg_dumper *dumper); @@ -76,30 +80,30 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason) { } -static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, +static inline bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, const char *line, size_t size, size_t *len) { return false; } -static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, +static inline bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, const char *line, size_t size, size_t *len) { return false; } -static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, +static inline bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, char *buf, size_t size, size_t *len) { return false; } -static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) +static inline void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter) { } -static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper) +static inline void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { } diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 315169d5e119..8544d7a55a57 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2101,7 +2101,7 @@ static int kdb_dmesg(int argc, const char **argv) int adjust = 0; int n = 0; int skip = 0; - struct kmsg_dumper dumper; + struct kmsg_dump_iter iter; size_t len; char buf[201]; @@ -2126,8 +2126,8 @@ static int kdb_dmesg(int argc, const char **argv) kdb_set(2, setargs); } - kmsg_dump_rewind_nolock(&dumper); - while (kmsg_dump_get_line_nolock(&dumper, 1, NULL, 0, NULL)) + kmsg_dump_rewind_nolock(&iter); + while (kmsg_dump_get_line_nolock(&iter, 1, NULL, 0, NULL)) n++; if (lines < 0) { @@ -2159,8 +2159,8 @@ static int kdb_dmesg(int argc, const char **argv) if (skip >= n || skip < 0) return 0; - kmsg_dump_rewind_nolock(&dumper); - while (kmsg_dump_get_line_nolock(&dumper, 1, buf, sizeof(buf), &len)) { + kmsg_dump_rewind_nolock(&iter); + while (kmsg_dump_get_line_nolock(&iter, 1, buf, sizeof(buf), &len)) { if (skip) { skip--; continue; diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ce4cc64ba7c9..b49dee256947 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3390,7 +3390,6 @@ EXPORT_SYMBOL_GPL(kmsg_dump_reason_str); void kmsg_dump(enum kmsg_dump_reason reason) { struct kmsg_dumper *dumper; - unsigned long flags; rcu_read_lock(); list_for_each_entry_rcu(dumper, &dump_list, list) { @@ -3407,12 +3406,6 @@ void kmsg_dump(enum kmsg_dump_reason reason) if (reason > max_reason) continue; - /* initialize iterator with data about the stored records */ - logbuf_lock_irqsave(flags); - dumper->cur_seq = latched_seq_read_nolock(&clear_seq); - dumper->next_seq = prb_next_seq(prb); - logbuf_unlock_irqrestore(flags); - /* invoke dumper which will iterate over records */ dumper->dump(dumper, reason); } @@ -3421,7 +3414,7 @@ void kmsg_dump(enum kmsg_dump_reason reason) /** * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) - * @dumper: registered kmsg dumper + * @iter: kmsg dump iterator * @syslog: include the "<4>" prefixes * @line: buffer to copy the line to * @size: maximum size of the buffer @@ -3438,24 +3431,28 @@ void kmsg_dump(enum kmsg_dump_reason reason) * * The function is similar to kmsg_dump_get_line(), but grabs no locks. */ -bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len) { + u64 min_seq = latched_seq_read_nolock(&clear_seq); struct printk_info info; unsigned int line_count; struct printk_record r; size_t l = 0; bool ret = false; + if (iter->cur_seq < min_seq) + iter->cur_seq = min_seq; + prb_rec_init_rd(&r, &info, line, size); /* Read text or count text lines? */ if (line) { - if (!prb_read_valid(prb, dumper->cur_seq, &r)) + if (!prb_read_valid(prb, iter->cur_seq, &r)) goto out; l = record_print_text(&r, syslog, printk_time); } else { - if (!prb_read_valid_info(prb, dumper->cur_seq, + if (!prb_read_valid_info(prb, iter->cur_seq, &info, &line_count)) { goto out; } @@ -3464,7 +3461,7 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, } - dumper->cur_seq = r.info->seq + 1; + iter->cur_seq = r.info->seq + 1; ret = true; out: if (len) @@ -3474,7 +3471,7 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, /** * kmsg_dump_get_line - retrieve one kmsg log line - * @dumper: registered kmsg dumper + * @iter: kmsg dump iterator * @syslog: include the "<4>" prefixes * @line: buffer to copy the line to * @size: maximum size of the buffer @@ -3489,14 +3486,14 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, * A return value of FALSE indicates that there are no more records to * read. */ -bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len) { unsigned long flags; bool ret; logbuf_lock_irqsave(flags); - ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); + ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len); logbuf_unlock_irqrestore(flags); return ret; @@ -3505,7 +3502,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line); /** * kmsg_dump_get_buffer - copy kmsg log lines - * @dumper: registered kmsg dumper + * @iter: kmsg dump iterator * @syslog: include the "<4>" prefixes * @buf: buffer to copy the line to * @size: maximum size of the buffer @@ -3522,9 +3519,10 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line); * A return value of FALSE indicates that there are no more records to * read. */ -bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, +bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, char *buf, size_t size, size_t *len_out) { + u64 min_seq = latched_seq_read_nolock(&clear_seq); struct printk_info info; struct printk_record r; unsigned long flags; @@ -3537,16 +3535,19 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, if (!buf || !size) goto out; + if (iter->cur_seq < min_seq) + iter->cur_seq = min_seq; + logbuf_lock_irqsave(flags); - if (prb_read_valid_info(prb, dumper->cur_seq, &info, NULL)) { - if (info.seq != dumper->cur_seq) { + if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) { + if (info.seq != iter->cur_seq) { /* messages are gone, move to first available one */ - dumper->cur_seq = info.seq; + iter->cur_seq = info.seq; } } /* last entry */ - if (dumper->cur_seq >= dumper->next_seq) { + if (iter->cur_seq >= iter->next_seq) { logbuf_unlock_irqrestore(flags); goto out; } @@ -3557,7 +3558,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, * because this function (by way of record_print_text()) will * not write more than size-1 bytes of text into @buf. */ - seq = find_first_fitting_seq(dumper->cur_seq, dumper->next_seq, + seq = find_first_fitting_seq(iter->cur_seq, iter->next_seq, size - 1, syslog, time); /* @@ -3570,7 +3571,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, len = 0; prb_for_each_record(seq, prb, seq, &r) { - if (r.info->seq >= dumper->next_seq) + if (r.info->seq >= iter->next_seq) break; len += record_print_text(&r, syslog, time); @@ -3579,7 +3580,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, prb_rec_init_rd(&r, &info, buf + len, size - len); } - dumper->next_seq = next_seq; + iter->next_seq = next_seq; ret = true; logbuf_unlock_irqrestore(flags); out: @@ -3591,7 +3592,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); /** * kmsg_dump_rewind_nolock - reset the iterator (unlocked version) - * @dumper: registered kmsg dumper + * @iter: kmsg dump iterator * * Reset the dumper's iterator so that kmsg_dump_get_line() and * kmsg_dump_get_buffer() can be called again and used multiple @@ -3599,26 +3600,26 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); * * The function is similar to kmsg_dump_rewind(), but grabs no locks. */ -void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) +void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter) { - dumper->cur_seq = latched_seq_read_nolock(&clear_seq); - dumper->next_seq = prb_next_seq(prb); + iter->cur_seq = latched_seq_read_nolock(&clear_seq); + iter->next_seq = prb_next_seq(prb); } /** * kmsg_dump_rewind - reset the iterator - * @dumper: registered kmsg dumper + * @iter: kmsg dump iterator * * Reset the dumper's iterator so that kmsg_dump_get_line() and * kmsg_dump_get_buffer() can be called again and used multiple * times within the same dumper.dump() callback. */ -void kmsg_dump_rewind(struct kmsg_dumper *dumper) +void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { unsigned long flags; logbuf_lock_irqsave(flags); - kmsg_dump_rewind_nolock(dumper); + kmsg_dump_rewind_nolock(iter); logbuf_unlock_irqrestore(flags); } EXPORT_SYMBOL_GPL(kmsg_dump_rewind); From patchwork Wed Mar 3 10:15:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 1446552 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; 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dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Dr8yg5cFDz3cYm for ; Wed, 3 Mar 2021 21:15:39 +1100 (AEDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1614766537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9CVCDvgkqaxh7MYJebjzfGDlcpHL5EV9JmU/3T5/E9o=; b=Zm7xKp9CT+sUU4WRzec8CVEpFrLLJdFNgYAi1a92dvtdqPPKabAr6dQ1ygaKwBhaQh1B7M vHeaI2YzUCOY3nHlbmeurQavz9gccOovBkvDoEsmUo+eyeYkpBEMpqPcH5Iw86ET2ZMpK0 V8XJq5OjwzoLNWgDpbJnl3zMaxlG0Bvevf/LKPWFu7UuD8/SSgX6tTh81/mRFyzmz2r9T4 bUxUgucGyycystzxjpWp2ddmSgxUTqCaZJICMULeqFqG8a1Yqn2vM0bg37svlJM0yq49XG h1ck627ETJj80c96ClUDLmUtcUcjHIGtXzAJ9RUPhWiy+KMwpf+tE3vnCpQx6g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1614766537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9CVCDvgkqaxh7MYJebjzfGDlcpHL5EV9JmU/3T5/E9o=; b=bVf+wnuWrrtIo4HglvFNUtHsGhnWYVuWdv8nO4uJMFQhqNPABIruxkBynt1DXoWmG7hPu5 lrRlsI5dtVWhuaDQ== To: Petr Mladek Subject: [PATCH next v4 14/15] printk: kmsg_dump: remove _nolock() variants Date: Wed, 3 Mar 2021 11:15:27 +0100 Message-Id: <20210303101528.29901-15-john.ogness@linutronix.de> In-Reply-To: <20210303101528.29901-1-john.ogness@linutronix.de> References: <20210303101528.29901-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sergey Senozhatsky , Douglas Anderson , Paul Mackerras , Kees Cook , Daniel Thompson , Madhavan Srinivasan , Jordan Niethe , Wei Li , Ravi Bangoria , Pavel Tatashin , Alistair Popple , Steven Rostedt , Davidlohr Bueso , Nicholas Piggin , Thomas Gleixner , Sumit Garg , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Jason Wessel , kgdb-bugreport@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, Mike Rapoport Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is no need for _nolock() variants. Remove these functions and switch all callers of the _nolock() variants. The functions without _nolock() were chosen because they are already exported to kernel modules. Signed-off-by: John Ogness Reviewed-by: Petr Mladek --- arch/powerpc/xmon/xmon.c | 4 +-- include/linux/kmsg_dump.h | 16 ---------- kernel/debug/kdb/kdb_main.c | 8 ++--- kernel/printk/printk.c | 60 +++++-------------------------------- 4 files changed, 14 insertions(+), 74 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 5978b90a885f..bf7d69625a2e 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3013,9 +3013,9 @@ dump_log_buf(void) catch_memory_errors = 1; sync(); - kmsg_dump_rewind_nolock(&iter); + kmsg_dump_rewind(&iter); xmon_start_pagination(); - while (kmsg_dump_get_line_nolock(&iter, false, buf, sizeof(buf), &len)) { + while (kmsg_dump_get_line(&iter, false, buf, sizeof(buf), &len)) { buf[len] = '\0'; printf("%s", buf); } diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 36c8c57e1051..906521c2329c 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -57,17 +57,12 @@ struct kmsg_dumper { #ifdef CONFIG_PRINTK void kmsg_dump(enum kmsg_dump_reason reason); -bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, - char *line, size_t size, size_t *len); - bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, char *line, size_t size, size_t *len); bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, char *buf, size_t size, size_t *len_out); -void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter); - void kmsg_dump_rewind(struct kmsg_dump_iter *iter); int kmsg_dump_register(struct kmsg_dumper *dumper); @@ -80,13 +75,6 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason) { } -static inline bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, - bool syslog, const char *line, - size_t size, size_t *len) -{ - return false; -} - static inline bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, const char *line, size_t size, size_t *len) { @@ -99,10 +87,6 @@ static inline bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog return false; } -static inline void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter) -{ -} - static inline void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { } diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 8544d7a55a57..67d9f2403b52 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2126,8 +2126,8 @@ static int kdb_dmesg(int argc, const char **argv) kdb_set(2, setargs); } - kmsg_dump_rewind_nolock(&iter); - while (kmsg_dump_get_line_nolock(&iter, 1, NULL, 0, NULL)) + kmsg_dump_rewind(&iter); + while (kmsg_dump_get_line(&iter, 1, NULL, 0, NULL)) n++; if (lines < 0) { @@ -2159,8 +2159,8 @@ static int kdb_dmesg(int argc, const char **argv) if (skip >= n || skip < 0) return 0; - kmsg_dump_rewind_nolock(&iter); - while (kmsg_dump_get_line_nolock(&iter, 1, buf, sizeof(buf), &len)) { + kmsg_dump_rewind(&iter); + while (kmsg_dump_get_line(&iter, 1, buf, sizeof(buf), &len)) { if (skip) { skip--; continue; diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 8994bc192b88..602de86d4e76 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3373,7 +3373,7 @@ void kmsg_dump(enum kmsg_dump_reason reason) } /** - * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) + * kmsg_dump_get_line - retrieve one kmsg log line * @iter: kmsg dump iterator * @syslog: include the "<4>" prefixes * @line: buffer to copy the line to @@ -3388,22 +3388,22 @@ void kmsg_dump(enum kmsg_dump_reason reason) * * A return value of FALSE indicates that there are no more records to * read. - * - * The function is similar to kmsg_dump_get_line(), but grabs no locks. */ -bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, - char *line, size_t size, size_t *len) +bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, + char *line, size_t size, size_t *len) { u64 min_seq = latched_seq_read_nolock(&clear_seq); struct printk_info info; unsigned int line_count; struct printk_record r; + unsigned long flags; size_t l = 0; bool ret = false; if (iter->cur_seq < min_seq) iter->cur_seq = min_seq; + printk_safe_enter_irqsave(flags); prb_rec_init_rd(&r, &info, line, size); /* Read text or count text lines? */ @@ -3424,40 +3424,11 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog, iter->cur_seq = r.info->seq + 1; ret = true; out: + printk_safe_exit_irqrestore(flags); if (len) *len = l; return ret; } - -/** - * kmsg_dump_get_line - retrieve one kmsg log line - * @iter: kmsg dump iterator - * @syslog: include the "<4>" prefixes - * @line: buffer to copy the line to - * @size: maximum size of the buffer - * @len: length of line placed into buffer - * - * Start at the beginning of the kmsg buffer, with the oldest kmsg - * record, and copy one record into the provided buffer. - * - * Consecutive calls will return the next available record moving - * towards the end of the buffer with the youngest messages. - * - * A return value of FALSE indicates that there are no more records to - * read. - */ -bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, - char *line, size_t size, size_t *len) -{ - unsigned long flags; - bool ret; - - printk_safe_enter_irqsave(flags); - ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len); - printk_safe_exit_irqrestore(flags); - - return ret; -} EXPORT_SYMBOL_GPL(kmsg_dump_get_line); /** @@ -3550,22 +3521,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, } EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); -/** - * kmsg_dump_rewind_nolock - reset the iterator (unlocked version) - * @iter: kmsg dump iterator - * - * Reset the dumper's iterator so that kmsg_dump_get_line() and - * kmsg_dump_get_buffer() can be called again and used multiple - * times within the same dumper.dump() callback. - * - * The function is similar to kmsg_dump_rewind(), but grabs no locks. - */ -void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter) -{ - iter->cur_seq = latched_seq_read_nolock(&clear_seq); - iter->next_seq = prb_next_seq(prb); -} - /** * kmsg_dump_rewind - reset the iterator * @iter: kmsg dump iterator @@ -3579,7 +3534,8 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter) unsigned long flags; printk_safe_enter_irqsave(flags); - kmsg_dump_rewind_nolock(iter); + iter->cur_seq = latched_seq_read_nolock(&clear_seq); + iter->next_seq = prb_next_seq(prb); printk_safe_exit_irqrestore(flags); } EXPORT_SYMBOL_GPL(kmsg_dump_rewind);