From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Shilovsky Subject: Re: [PATCH v2 07/16] CIFS: Separate filling pages from iovec write Date: Mon, 21 Jul 2014 10:48:25 +0400 Message-ID: References: <1403863073-19526-1-git-send-email-pshilovsky@samba.org> <1403863073-19526-8-git-send-email-pshilovsky@samba.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-cifs To: Shirish Pargaonkar Return-path: In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: 2014-07-21 7:59 GMT+04:00 Shirish Pargaonkar : > Like put_page() for rc = 0 unused pages was moved to wdata_fill_from_iovec(), > probably move put_page in case of -EFAULT also to wdata_fill_from_iovec()? > So just kfree and break if(rc)? > Also, wdata_fill_from_iovec() does not need rc, it can just return 0 > in case of no error? Yes, or may be move the last loop from wdata_fill_from_iovec() to the caller. > > > On Fri, Jun 27, 2014 at 4:57 AM, Pavel Shilovsky wrote: >> Signed-off-by: Pavel Shilovsky >> --- >> fs/cifs/file.c | 85 +++++++++++++++++++++++++++++++++------------------------- >> 1 file changed, 48 insertions(+), 37 deletions(-) >> >> diff --git a/fs/cifs/file.c b/fs/cifs/file.c >> index 21f9be0..e2a735a 100644 >> --- a/fs/cifs/file.c >> +++ b/fs/cifs/file.c >> @@ -2423,11 +2423,56 @@ cifs_uncached_retry_writev(struct cifs_writedata *wdata) >> return rc; >> } >> >> +static int >> +wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from, >> + size_t *len, unsigned long nr_pages) >> +{ >> + int rc = 0; >> + size_t save_len, copied, bytes, cur_len = *len; >> + unsigned long i; >> + >> + save_len = cur_len; >> + for (i = 0; i < nr_pages; i++) { >> + bytes = min_t(const size_t, cur_len, PAGE_SIZE); >> + copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from); >> + cur_len -= copied; >> + /* >> + * If we didn't copy as much as we expected, then that >> + * may mean we trod into an unmapped area. Stop copying >> + * at that point. On the next pass through the big >> + * loop, we'll likely end up getting a zero-length >> + * write and bailing out of it. >> + */ >> + if (copied < bytes) >> + break; >> + } >> + cur_len = save_len - cur_len; >> + *len = cur_len; >> + >> + /* >> + * If we have no data to send, then that probably means that >> + * the copy above failed altogether. That's most likely because >> + * the address in the iovec was bogus. Return -EFAULT and let >> + * the caller free anything we allocated and bail out. >> + */ >> + if (!cur_len) >> + return -EFAULT; >> + >> + /* >> + * i + 1 now represents the number of pages we actually used in >> + * the copy phase above. Bring nr_pages down to that, and free >> + * any pages that we didn't use. >> + */ >> + for ( ; nr_pages > i + 1; nr_pages--) >> + put_page(wdata->pages[nr_pages - 1]); >> + return rc; >> +} Ah, nr_pages is updated here but we don't return it to the caller! That should be fixed at first. >> + >> static ssize_t >> cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset) >> { >> unsigned long nr_pages, i; >> - size_t bytes, copied, len, cur_len; >> + size_t len, cur_len; >> ssize_t total_written = 0; >> loff_t offset; >> struct cifsFileInfo *open_file; >> @@ -2464,8 +2509,6 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset) >> pid = current->tgid; >> >> do { >> - size_t save_len; >> - >> nr_pages = get_numpages(cifs_sb->wsize, len, &cur_len); >> wdata = cifs_writedata_alloc(nr_pages, >> cifs_uncached_writev_complete); >> @@ -2480,46 +2523,14 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset) >> break; >> } >> >> - save_len = cur_len; >> - for (i = 0; i < nr_pages; i++) { >> - bytes = min_t(size_t, cur_len, PAGE_SIZE); >> - copied = copy_page_from_iter(wdata->pages[i], 0, bytes, >> - from); >> - cur_len -= copied; >> - /* >> - * If we didn't copy as much as we expected, then that >> - * may mean we trod into an unmapped area. Stop copying >> - * at that point. On the next pass through the big >> - * loop, we'll likely end up getting a zero-length >> - * write and bailing out of it. >> - */ >> - if (copied < bytes) >> - break; >> - } >> - cur_len = save_len - cur_len; >> - >> - /* >> - * If we have no data to send, then that probably means that >> - * the copy above failed altogether. That's most likely because >> - * the address in the iovec was bogus. Set the rc to -EFAULT, >> - * free anything we allocated and bail out. >> - */ >> - if (!cur_len) { >> + rc = wdata_fill_from_iovec(wdata, from, &cur_len, nr_pages); >> + if (rc) { >> for (i = 0; i < nr_pages; i++) >> put_page(wdata->pages[i]); >> kfree(wdata); >> - rc = -EFAULT; >> break; >> } >> >> - /* >> - * i + 1 now represents the number of pages we actually used in >> - * the copy phase above. Bring nr_pages down to that, and free >> - * any pages that we didn't use. >> - */ >> - for ( ; nr_pages > i + 1; nr_pages--) >> - put_page(wdata->pages[nr_pages - 1]); >> - >> wdata->sync_mode = WB_SYNC_ALL; >> wdata->nr_pages = nr_pages; >> wdata->offset = (__u64)offset; >> -- >> 1.8.1.2 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in >> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- Best regards, Pavel Shilovsky.