| Message ID | 1441787886-7214-4-git-send-email-linux@rasmusvillemoes.dk |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 2015-09-09 at 10:38 +0200, Rasmus Villemoes wrote: > The double memset is a little ugly; using kzalloc avoids it altogether. [] > diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c [] > @@ -1859,14 +1859,11 @@ oom: > return; > } > > - mc_spec = kmalloc(0x200, GFP_ATOMIC); > + mc_spec = kzalloc(0x200, GFP_ATOMIC); > if (mc_spec == NULL) > goto oom; > mc_other = mc_spec + (0x100 >> 2); This sure looks wrong as it sets a pointer to unallocated memory. > - memset(mc_spec, 0, 0x100); > - memset(mc_other, 0, 0x100); So this does a memset of random memory. for (i = 0; i < 0x100; i += 4) { wrl(mp, SPECIAL_MCAST_TABLE(mp->port_num) + i, mc_spec[i >> 2]); wrl(mp, OTHER_MCAST_TABLE(mp->port_num) + i, mc_other[i >> 2]); } -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Sep 09 2015, Joe Perches <joe@perches.com> wrote: > On Wed, 2015-09-09 at 10:38 +0200, Rasmus Villemoes wrote: >> The double memset is a little ugly; using kzalloc avoids it altogether. > [] >> diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c > [] >> @@ -1859,14 +1859,11 @@ oom: >> return; >> } >> >> - mc_spec = kmalloc(0x200, GFP_ATOMIC); >> + mc_spec = kzalloc(0x200, GFP_ATOMIC); >> if (mc_spec == NULL) >> goto oom; >> mc_other = mc_spec + (0x100 >> 2); > > This sure looks wrong as it sets a pointer > to unallocated memory. > >> - memset(mc_spec, 0, 0x100); >> - memset(mc_other, 0, 0x100); > > So this does a memset of random memory. > Huh? mc_spec and mc_other are u32*, we allocate 0x200 = 512 bytes = 128 u32s, and pointer arithmetic makes mc_other point to the latter 64. Then the memory is cleared 256 bytes at a time. It's unusual and slightly obfuscated code, but I don't think it's wrong. > > for (i = 0; i < 0x100; i += 4) { > wrl(mp, SPECIAL_MCAST_TABLE(mp->port_num) + i, mc_spec[i >> 2]); > wrl(mp, OTHER_MCAST_TABLE(mp->port_num) + i, mc_other[i >> 2]); > } I'd probably have written that as for (i = 0; i < 64; ++i) { wrl(mp, SPECIAL_MCAST_TABLE(mp->port_num) + 4*i, mc_spec[i]); wrl(mp, OTHER_MCAST_TABLE(mp->port_num) + 4*i, mc_other[i]); } but again, I don't think it's wrong [haven't checked what SPECIAL_MCAST_TABLE/OTHER_MCAST_TABLE do, though]. Rasmus -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2015-09-09 at 20:34 +0200, Rasmus Villemoes wrote: > mc_spec and mc_other are u32*, we allocate 0x200 = 512 bytes = 128 > u32s, and pointer arithmetic makes mc_other point to the latter 64. Then > the memory is cleared 256 bytes at a time. > > It's unusual and slightly obfuscated code, but I don't think it's > wrong. Right, misread. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c index d52639bc491f..960169efe636 100644 --- a/drivers/net/ethernet/marvell/mv643xx_eth.c +++ b/drivers/net/ethernet/marvell/mv643xx_eth.c @@ -1859,14 +1859,11 @@ oom: return; } - mc_spec = kmalloc(0x200, GFP_ATOMIC); + mc_spec = kzalloc(0x200, GFP_ATOMIC); if (mc_spec == NULL) goto oom; mc_other = mc_spec + (0x100 >> 2); - memset(mc_spec, 0, 0x100); - memset(mc_other, 0, 0x100); - netdev_for_each_mc_addr(ha, dev) { u8 *a = ha->addr; u32 *table;
The double memset is a little ugly; using kzalloc avoids it altogether. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- drivers/net/ethernet/marvell/mv643xx_eth.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)