* [PATCH] lib/scatterlist: Avoid a double memset
@ 2020-09-20 7:15 Christophe JAILLET
2020-09-20 7:28 ` Joe Perches
0 siblings, 1 reply; 4+ messages in thread
From: Christophe JAILLET @ 2020-09-20 7:15 UTC (permalink / raw)
To: akpm, natechancellor, geert+renesas
Cc: linux-kernel, kernel-janitors, Christophe JAILLET
'sgl' is zeroed a few lines below in 'sg_init_table()'. There is no need to
clear it twice.
Remove the redundant initialization.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
lib/scatterlist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 5d63a8857f36..d94628fa3349 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -504,7 +504,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length,
nalloc++;
}
sgl = kmalloc_array(nalloc, sizeof(struct scatterlist),
- (gfp & ~GFP_DMA) | __GFP_ZERO);
+ gfp & ~GFP_DMA);
if (!sgl)
return NULL;
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] lib/scatterlist: Avoid a double memset
2020-09-20 7:15 [PATCH] lib/scatterlist: Avoid a double memset Christophe JAILLET
@ 2020-09-20 7:28 ` Joe Perches
2020-09-20 8:32 ` Julia Lawall
0 siblings, 1 reply; 4+ messages in thread
From: Joe Perches @ 2020-09-20 7:28 UTC (permalink / raw)
To: Christophe JAILLET, akpm, natechancellor, geert+renesas
Cc: linux-kernel, kernel-janitors
On Sun, 2020-09-20 at 09:15 +0200, Christophe JAILLET wrote:
> 'sgl' is zeroed a few lines below in 'sg_init_table()'. There is no need to
> clear it twice.
>
> Remove the redundant initialization.
I didn't look very thoroughly, but there are at least
a few more of these with kcalloc and kzalloc like
block/bsg-lib.c- size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
block/bsg-lib.c-
block/bsg-lib.c- BUG_ON(!req->nr_phys_segments);
block/bsg-lib.c-
block/bsg-lib.c- buf->sg_list = kzalloc(sz, GFP_KERNEL);
block/bsg-lib.c- if (!buf->sg_list)
block/bsg-lib.c- return -ENOMEM;
block/bsg-lib.c: sg_init_table(buf->sg_list, req->nr_phys_segments);
---
drivers/target/target_core_rd.c- sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
drivers/target/target_core_rd.c- GFP_KERNEL);
drivers/target/target_core_rd.c- if (!sg)
drivers/target/target_core_rd.c- return -ENOMEM;
drivers/target/target_core_rd.c-
drivers/target/target_core_rd.c: sg_init_table(sg, sg_per_table + chain_entry);
---
net/rds/rdma.c- sg = kcalloc(nents, sizeof(*sg), GFP_KERNEL);
net/rds/rdma.c- if (!sg) {
net/rds/rdma.c- ret = -ENOMEM;
net/rds/rdma.c- goto out;
net/rds/rdma.c- }
net/rds/rdma.c- WARN_ON(!nents);
net/rds/rdma.c: sg_init_table(sg, nents);
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] lib/scatterlist: Avoid a double memset
2020-09-20 7:28 ` Joe Perches
@ 2020-09-20 8:32 ` Julia Lawall
2020-09-20 8:54 ` Christophe JAILLET
0 siblings, 1 reply; 4+ messages in thread
From: Julia Lawall @ 2020-09-20 8:32 UTC (permalink / raw)
To: Joe Perches
Cc: Christophe JAILLET, akpm, natechancellor, geert+renesas,
linux-kernel, kernel-janitors
On Sun, 20 Sep 2020, Joe Perches wrote:
> On Sun, 2020-09-20 at 09:15 +0200, Christophe JAILLET wrote:
> > 'sgl' is zeroed a few lines below in 'sg_init_table()'. There is no need to
> > clear it twice.
> >
> > Remove the redundant initialization.
>
> I didn't look very thoroughly, but there are at least
> a few more of these with kcalloc and kzalloc like
>
> block/bsg-lib.c- size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
> block/bsg-lib.c-
> block/bsg-lib.c- BUG_ON(!req->nr_phys_segments);
> block/bsg-lib.c-
> block/bsg-lib.c- buf->sg_list = kzalloc(sz, GFP_KERNEL);
> block/bsg-lib.c- if (!buf->sg_list)
> block/bsg-lib.c- return -ENOMEM;
> block/bsg-lib.c: sg_init_table(buf->sg_list, req->nr_phys_segments);
> ---
> drivers/target/target_core_rd.c- sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
> drivers/target/target_core_rd.c- GFP_KERNEL);
> drivers/target/target_core_rd.c- if (!sg)
> drivers/target/target_core_rd.c- return -ENOMEM;
> drivers/target/target_core_rd.c-
> drivers/target/target_core_rd.c: sg_init_table(sg, sg_per_table + chain_entry);
> ---
> net/rds/rdma.c- sg = kcalloc(nents, sizeof(*sg), GFP_KERNEL);
> net/rds/rdma.c- if (!sg) {
> net/rds/rdma.c- ret = -ENOMEM;
> net/rds/rdma.c- goto out;
> net/rds/rdma.c- }
> net/rds/rdma.c- WARN_ON(!nents);
> net/rds/rdma.c: sg_init_table(sg, nents);
I found 16 occurrences in the following files:
net/rds/rdma.c
drivers/infiniband/hw/efa/efa_verbs.c
drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
drivers/misc/mic/scif/scif_nodeqp.c
block/bsg-lib.c
drivers/dma/sh/rcar-dmac.c
drivers/spi/spi-topcliff-pch.c
net/sunrpc/xprtrdma/frwr_ops.c
drivers/dma/imx-dma.c
drivers/pci/p2pdma.c
drivers/dma/sh/shdma-base.c
drivers/target/target_core_rd.c
drivers/media/common/saa7146/saa7146_core.c
drivers/tty/serial/pch_uart.c
drivers/net/wireless/intel/iwlwifi/fw/dbg.c
julia
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] lib/scatterlist: Avoid a double memset
2020-09-20 8:32 ` Julia Lawall
@ 2020-09-20 8:54 ` Christophe JAILLET
0 siblings, 0 replies; 4+ messages in thread
From: Christophe JAILLET @ 2020-09-20 8:54 UTC (permalink / raw)
To: Julia Lawall, Joe Perches
Cc: akpm, natechancellor, geert+renesas, linux-kernel, kernel-janitors
Le 20/09/2020 à 10:32, Julia Lawall a écrit :
>
>
> On Sun, 20 Sep 2020, Joe Perches wrote:
>
>> On Sun, 2020-09-20 at 09:15 +0200, Christophe JAILLET wrote:
>>> 'sgl' is zeroed a few lines below in 'sg_init_table()'. There is no need to
>>> clear it twice.
>>>
>>> Remove the redundant initialization.
>>
>> I didn't look very thoroughly, but there are at least
>> a few more of these with kcalloc and kzalloc like
>>
>> block/bsg-lib.c- size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
>> block/bsg-lib.c-
>> block/bsg-lib.c- BUG_ON(!req->nr_phys_segments);
>> block/bsg-lib.c-
>> block/bsg-lib.c- buf->sg_list = kzalloc(sz, GFP_KERNEL);
>> block/bsg-lib.c- if (!buf->sg_list)
>> block/bsg-lib.c- return -ENOMEM;
>> block/bsg-lib.c: sg_init_table(buf->sg_list, req->nr_phys_segments);
>> ---
>> drivers/target/target_core_rd.c- sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
>> drivers/target/target_core_rd.c- GFP_KERNEL);
>> drivers/target/target_core_rd.c- if (!sg)
>> drivers/target/target_core_rd.c- return -ENOMEM;
>> drivers/target/target_core_rd.c-
>> drivers/target/target_core_rd.c: sg_init_table(sg, sg_per_table + chain_entry);
>> ---
>> net/rds/rdma.c- sg = kcalloc(nents, sizeof(*sg), GFP_KERNEL);
>> net/rds/rdma.c- if (!sg) {
>> net/rds/rdma.c- ret = -ENOMEM;
>> net/rds/rdma.c- goto out;
>> net/rds/rdma.c- }
>> net/rds/rdma.c- WARN_ON(!nents);
>> net/rds/rdma.c: sg_init_table(sg, nents);
>
> I found 16 occurrences in the following files:
>
> net/rds/rdma.c
> drivers/infiniband/hw/efa/efa_verbs.c
> drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> drivers/misc/mic/scif/scif_nodeqp.c
> block/bsg-lib.c
> drivers/dma/sh/rcar-dmac.c
> drivers/spi/spi-topcliff-pch.c
> net/sunrpc/xprtrdma/frwr_ops.c
> drivers/dma/imx-dma.c
> drivers/pci/p2pdma.c
> drivers/dma/sh/shdma-base.c
> drivers/target/target_core_rd.c
> drivers/media/common/saa7146/saa7146_core.c
> drivers/tty/serial/pch_uart.c
> drivers/net/wireless/intel/iwlwifi/fw/dbg.c
>
> julia
>
Also in:
sound/soc/sprd/sprd-pcm-dma.c
sound/soc/sprd/sprd-pcm-compress.c
which are a bit tricky. It also uses some, IMHO, pointless devm_ functions.
Feel free to propose patches. I'm not focused on that at the moment.
CJ
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-09-20 7:15 [PATCH] lib/scatterlist: Avoid a double memset Christophe JAILLET
2020-09-20 7:28 ` Joe Perches
2020-09-20 8:32 ` Julia Lawall
2020-09-20 8:54 ` Christophe JAILLET
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