Messages in this thread | | | Subject | Re: [PATCH 22/31] fs/ntfs: use kmemdup rather than duplicating its implementation | From | Andrzej Hajda <> | Date | Thu, 24 Sep 2015 10:34:33 +0200 |
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On 09/23/2015 12:21 PM, Anton Altaparmakov wrote: > Hi Andrzej, > > Thanks for your patch. It looks fine though I don't quite see the point of it to be honest. > > It actually adds an additional function call (kmemdup() is not inline) just to save 1 line of source code in the driver and I don't think it improves readability or anything so why bother? What does it gain?
kmemdup replaces combo (kmalloc + memdup) with one call. The patch follows quite common practice of abstracting out common patterns.
Regards Andrzej
> > Best regards, > > Anton > >> On 7 Aug 2015, at 08:59, Andrzej Hajda <a.hajda@samsung.com> wrote: >> >> The patch was generated using fixed coccinelle semantic patch >> scripts/coccinelle/api/memdup.cocci [1]. >> >> [1]: http://permalink.gmane.org/gmane.linux.kernel/2014320 >> >> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> >> --- >> fs/ntfs/dir.c | 7 +++---- >> 1 file changed, 3 insertions(+), 4 deletions(-) >> >> diff --git a/fs/ntfs/dir.c b/fs/ntfs/dir.c >> index 9e38daf..2b7fef0 100644 >> --- a/fs/ntfs/dir.c >> +++ b/fs/ntfs/dir.c >> @@ -1172,14 +1172,13 @@ static int ntfs_readdir(struct file *file, struct dir_context *actor) >> * map the mft record without deadlocking. >> */ >> rc = le32_to_cpu(ctx->attr->data.resident.value_length); >> - ir = kmalloc(rc, GFP_NOFS); >> + /* Copy the index root value (it has been verified in read_inode). */ >> + ir = kmemdup((u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset), >> + rc, GFP_NOFS); >> if (unlikely(!ir)) { >> err = -ENOMEM; >> goto err_out; >> } >> - /* Copy the index root value (it has been verified in read_inode). */ >> - memcpy(ir, (u8*)ctx->attr + >> - le16_to_cpu(ctx->attr->data.resident.value_offset), rc); >> ntfs_attr_put_search_ctx(ctx); >> unmap_mft_record(ndir); >> ctx = NULL; >> -- >> 1.9.1
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