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SubjectRe: [PATCH] lib/scatterlist: Avoid a double memset
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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

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