Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932336Ab0FBMUp (ORCPT ); Wed, 2 Jun 2010 08:20:45 -0400 Received: from crca.org.au ([74.207.252.120]:52988 "EHLO crca.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932203Ab0FBMUl (ORCPT ); Wed, 2 Jun 2010 08:20:41 -0400 X-Bogosity: Ham, spamicity=0.000000 From: Nigel Cunningham To: "Rafael J. Wysocki" , Linux PM , LKML , TuxOnIce-devel Subject: [PATCH 16/21] Hibernation: Replace bio chain Date: Wed, 2 Jun 2010 22:19:15 +1000 Message-Id: <1275481160-31150-17-git-send-email-nigel@tuxonice.net> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1275481160-31150-1-git-send-email-nigel@tuxonice.net> References: <1275481160-31150-1-git-send-email-nigel@tuxonice.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4500 Lines: 149 Replace the bio_chain concept with: (1) simple atomic_t recording how many pages are in flight (2) a wait queue for waiting for all I/O to complete (3) a custom completion routine that frees bio structs and pages used for async writes as they complete, undates the atomic_t and wakes any waiters. Signed-off-by: Nigel Cunningham --- kernel/power/block_io.c | 77 ++++++++++++++++++++++++++++------------------ 1 files changed, 47 insertions(+), 30 deletions(-) diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c index 9028f74..c9569e5 100644 --- a/kernel/power/block_io.c +++ b/kernel/power/block_io.c @@ -16,23 +16,61 @@ #include "extents.h" #include "block_io.h" -static struct bio *bio_chain; - static char *hib_ppio_buffer; static int hib_ppio_buffer_posn; int hib_prepare_buffer(void); void hib_free_buffer(void); +static atomic_t hib_io_in_progress; +static DECLARE_WAIT_QUEUE_HEAD(num_in_progress_wait); + +/** + * hib_end_bio - bio completion function. + * @bio: bio that has completed. + * @err: Error value. Yes, like end_swap_bio_read, we ignore it. + * + * Function called by the block driver from interrupt context when I/O is + * completed. If we were writing the page, we want to free it and will have + * set bio->bi_private to the parameter we should use in telling the page + * allocation accounting code what the page was allocated for. If we're + * reading the page, it will be in the singly linked list made from + * page->private pointers. + **/ +static void hib_end_bio(struct bio *bio, int err) +{ + const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + struct page *page = bio->bi_io_vec[0].bv_page; + + if (!uptodate) { + SetPageError(page); + ClearPageUptodate(page); + printk(KERN_ALERT "I/O on swap-device (%u:%u:%Lu)\n", + imajor(bio->bi_bdev->bd_inode), + iminor(bio->bi_bdev->bd_inode), + (unsigned long long)bio->bi_sector); + } else { + SetPageUptodate(page); + } + unlock_page(page); + bio_put(bio); + + if (bio->bi_private) + __free_page(page); + + atomic_dec(&hib_io_in_progress); + wake_up(&num_in_progress_wait); +} + /** * submit - submit BIO request. * @rw: READ or WRITE. * @off physical offset of page. * @page: page we're reading or writing. - * @bio_chain: list of pending biod (for async reading) + * @sync: whether the i/o should be done synchronously * * Straight from the textbook - allocate and initialize the bio. * If we're reading, make sure the page is marked as dirty. - * Then submit it and, if @bio_chain == NULL, wait. + * Then submit it and, if @sync, wait. */ static int submit(int rw, struct block_device *bdev, sector_t sector, struct page *page, int sync) @@ -43,7 +81,8 @@ static int submit(int rw, struct block_device *bdev, sector_t sector, bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1); bio->bi_sector = sector; bio->bi_bdev = bdev; - bio->bi_end_io = end_swap_bio_read; + bio->bi_private = (void *) (rw && !sync); + bio->bi_end_io = hib_end_bio; if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { printk(KERN_ERR "PM: Adding page to bio failed at %llu\n", @@ -54,6 +93,7 @@ static int submit(int rw, struct block_device *bdev, sector_t sector, lock_page(page); bio_get(bio); + atomic_inc(&hib_io_in_progress); if (sync) { submit_bio(bio_rw, bio); @@ -64,8 +104,6 @@ static int submit(int rw, struct block_device *bdev, sector_t sector, } else { if (rw == READ) get_page(page); /* These pages are freed later */ - bio->bi_private = bio_chain; - bio_chain = bio; submit_bio(bio_rw, bio); } return 0; @@ -85,29 +123,8 @@ int hib_bio_write_page(pgoff_t page_off, void *addr, int sync) int hib_wait_on_bio_chain(void) { - struct bio *bio; - struct bio *next_bio; - int ret = 0; - - if (bio_chain == NULL) - return 0; - - bio = bio_chain; - - while (bio) { - struct page *page; - - next_bio = bio->bi_private; - page = bio->bi_io_vec[0].bv_page; - wait_on_page_locked(page); - if (!PageUptodate(page) || PageError(page)) - ret = -EIO; - put_page(page); - bio_put(bio); - bio = next_bio; - } - bio_chain = NULL; - return ret; + wait_event(num_in_progress_wait, !atomic_read(&hib_io_in_progress)); + return 0; } /* -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/