On Fri, Oct 30, 2020 at 09:40:08PM -0600, Jens Axboe wrote:
On 10/30/20 7:51 AM, Naohiro Aota wrote:
From: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Add bio_add_zone_append_page(), a wrapper around bio_add_hw_page() which
is intended to be used by file systems that directly add pages to a bio
instead of using bio_iov_iter_get_pages().
Not sure what this is for, since I'm only on one patch in the series...
I'm sorry for the missing context. This patch is for this series.
https://lore.kernel.org/linux-btrfs/cover.1604065156.git.naohiro.aota@xxxxxxx/T/
This patch uses bio_add_zone_append_page in place of bio_add_page for zoned
device.
https://lore.kernel.org/linux-btrfs/cover.1604065156.git.naohiro.aota@xxxxxxx/T/#m88184d5dd11ac30c0878582898cd9d6f7cbc21fc
+/**
+ * bio_add_zone_append_page - attempt to add page to zone-append bio
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * Attempt to add a page to the bio_vec maplist of a bio that will be submitted
+ * for a zone-append request. This can fail for a number of reasons, such as the
+ * bio being full or the target block device is not a zoned block device or
+ * other limitations of the target block device. The target block device must
+ * allow bio's up to PAGE_SIZE, so it is always possible to add a single page
+ * to an empty bio.
+ */
This should include a
Return value:
section, explaining how it returns number of bytes added (and why 0 is thus
a failure case).
+int bio_add_zone_append_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
Should this return unsigned int? If not, how would it work if someone
asked for INT_MAX + 4k.
--
Jens Axboe
