| Message ID | 1ff02889-4c01-acb6-cfc0-48433a86bdf8@asilaycomputing.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi David, I think my previous email may have failed to send. Can you merge my patch below? It's a minor update that I think improves readability. Thanks, Sahil On 04/19/2017 05:43 AM, Sahil Kang wrote: > Hi, > > This is my first patch so it's a minor code change. > I think removing the early continue from the loop makes the function a > little easier to follow. > Please have a look and I'd appreciate any feedback. > > Thanks, > Sahil > > > From 98afe83a570180e841fefe3fd48d450accc42ea3 Mon Sep 17 00:00:00 2001 > From: Sahil Kang <sahil.kang@asilaycomputing.com> > Date: Wed, 19 Apr 2017 04:47:00 -0700 > Subject: [PATCH] Tidy while loop in end_compressed_writeback > > Instead of continuing early in the loop when ret is 0, > we can decrement/increment nr_pages/index by 1 at the ending. > The for loop will not execute when ret is 0 anyway. > > Signed-off-by: Sahil Kang <sahil.kang@asilaycomputing.com> > --- > fs/btrfs/compression.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c > index c473c42..c653297 100644 > --- a/fs/btrfs/compression.c > +++ b/fs/btrfs/compression.c > @@ -238,17 +238,14 @@ static noinline void > end_compressed_writeback(struct inode *inode, > ret = find_get_pages_contig(inode->i_mapping, index, > min_t(unsigned long, > nr_pages, ARRAY_SIZE(pages)), pages); > - if (ret == 0) { > - nr_pages -= 1; > - index += 1; > - continue; > - } > for (i = 0; i < ret; i++) { > if (cb->errors) > SetPageError(pages[i]); > end_page_writeback(pages[i]); > page_cache_release(pages[i]); > } > + > + ret = ret ? ret : 1; /* set ret to 1 if it's 0 */ > nr_pages -= ret; > index += ret; > } -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Chris, Would you merge my patch below? It's a minor update to improve the loop's readability. Thanks, Sahil On 04/19/2017 05:43 AM, Sahil Kang wrote: > Hi, > > This is my first patch so it's a minor code change. > I think removing the early continue from the loop makes the function a > little easier to follow. > Please have a look and I'd appreciate any feedback. > > Thanks, > Sahil > > > From 98afe83a570180e841fefe3fd48d450accc42ea3 Mon Sep 17 00:00:00 2001 > From: Sahil Kang <sahil.kang@asilaycomputing.com> > Date: Wed, 19 Apr 2017 04:47:00 -0700 > Subject: [PATCH] Tidy while loop in end_compressed_writeback > > Instead of continuing early in the loop when ret is 0, > we can decrement/increment nr_pages/index by 1 at the ending. > The for loop will not execute when ret is 0 anyway. > > Signed-off-by: Sahil Kang <sahil.kang@asilaycomputing.com> > --- > fs/btrfs/compression.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c > index c473c42..c653297 100644 > --- a/fs/btrfs/compression.c > +++ b/fs/btrfs/compression.c > @@ -238,17 +238,14 @@ static noinline void > end_compressed_writeback(struct inode *inode, > ret = find_get_pages_contig(inode->i_mapping, index, > min_t(unsigned long, > nr_pages, ARRAY_SIZE(pages)), pages); > - if (ret == 0) { > - nr_pages -= 1; > - index += 1; > - continue; > - } > for (i = 0; i < ret; i++) { > if (cb->errors) > SetPageError(pages[i]); > end_page_writeback(pages[i]); > page_cache_release(pages[i]); > } > + > + ret = ret ? ret : 1; /* set ret to 1 if it's 0 */ > nr_pages -= ret; > index += ret; > } -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Apr 19, 2017 at 05:43:19AM -0700, Sahil Kang wrote: > This is my first patch so it's a minor code change. > I think removing the early continue from the loop makes the function a > little easier to follow. I think the opposite. In the current code, it's clear that if ret is 0, then there's a shortcut. While your code change is functionally equivalent, it takes a bit more time to see that the for loop does nothing if ret == 0 and overall it looks like we don't handle the return value coming from find_get_pages_contig, in exchange for some ?: trickery that requires a comment. So I don't think this patch makes code better and I'm not going to apply it, sorry. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
I didn't consider it before, but I agree with your point on explicitly handling the return value from find_get_pages_contig. Thanks for looking over it, Sahil -------- Original Message -------- From: David Sterba <dsterba@suse.cz> Sent: May 2, 2017 9:01:34 AM PDT To: Sahil Kang <sahil.kang@asilaycomputing.com> Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] Tidy while loop in end_compressed_writeback On Wed, Apr 19, 2017 at 05:43:19AM -0700, Sahil Kang wrote: > This is my first patch so it's a minor code change. > I think removing the early continue from the loop makes the function a > little easier to follow. I think the opposite. In the current code, it's clear that if ret is 0, then there's a shortcut. While your code change is functionally equivalent, it takes a bit more time to see that the for loop does nothing if ret == 0 and overall it looks like we don't handle the return value coming from find_get_pages_contig, in exchange for some ?: trickery that requires a comment. So I don't think this patch makes code better and I'm not going to apply it, sorry. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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/fs/btrfs/compression.c b/fs/btrfs/compression.c index c473c42..c653297 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -238,17 +238,14 @@ static noinline void end_compressed_writeback(struct inode *inode, ret = find_get_pages_contig(inode->i_mapping, index, min_t(unsigned long, nr_pages, ARRAY_SIZE(pages)), pages); - if (ret == 0) { - nr_pages -= 1; - index += 1; - continue; - } for (i = 0; i < ret; i++) { if (cb->errors) SetPageError(pages[i]); end_page_writeback(pages[i]); page_cache_release(pages[i]); } + + ret = ret ? ret : 1; /* set ret to 1 if it's 0 */ nr_pages -= ret; index += ret;