From 0c12185728d602c27cd12a845249e7f37197f71f Mon Sep 17 00:00:00 2001 From: Hsin-Yi Wang Date: Fri, 17 Jun 2022 16:38:09 +0800 Subject: [PATCH] Revert "squashfs: provide backing_dev_info in order to disable read-ahead" Patch series "Implement readahead for squashfs", v7. Commit 9eec1d897139("squashfs: provide backing_dev_info in order to disable read-ahead") mitigates the performance drop issue for squashfs by closing readahead for it. This series implements readahead callback for squashfs. This patch (of 4): This reverts 9eec1d897139e5 ("squashfs: provide backing_dev_info in order to disable read-ahead"). Revert closing the readahead to squashfs since the readahead callback for squashfs is implemented. Link: https://lkml.kernel.org/r/20220617083810.337573-1-hsinyi@chromium.org Link: https://lkml.kernel.org/r/20220617083810.337573-2-hsinyi@chromium.org Signed-off-by: Hsin-Yi Wang Suggested-by: Xiongwei Song Cc: Phillip Lougher Cc: Matthew Wilcox Cc: Marek Szyprowski Cc: Zheng Liang Cc: Zhang Yi Cc: Hou Tao Cc: Miao Xie Cc: kernel test robot Signed-off-by: Andrew Morton --- fs/squashfs/super.c | 33 --------------------------------- 1 file changed, 33 deletions(-) diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c index 6d594ba..32565da 100644 --- a/fs/squashfs/super.c +++ b/fs/squashfs/super.c @@ -29,7 +29,6 @@ #include #include #include -#include #include "squashfs_fs.h" #include "squashfs_fs_sb.h" @@ -113,24 +112,6 @@ static const struct squashfs_decompressor *supported_squashfs_filesystem( return decompressor; } -static int squashfs_bdi_init(struct super_block *sb) -{ - int err; - unsigned int major = MAJOR(sb->s_dev); - unsigned int minor = MINOR(sb->s_dev); - - bdi_put(sb->s_bdi); - sb->s_bdi = &noop_backing_dev_info; - - err = super_setup_bdi_name(sb, "squashfs_%u_%u", major, minor); - if (err) - return err; - - sb->s_bdi->ra_pages = 0; - sb->s_bdi->io_pages = 0; - - return 0; -} static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc) { @@ -146,20 +127,6 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc) TRACE("Entered squashfs_fill_superblock\n"); - /* - * squashfs provides 'backing_dev_info' in order to disable read-ahead. For - * squashfs, I/O is not deferred, it is done immediately in read_folio, - * which means the user would always have to wait their own I/O. So the effect - * of readahead is very weak for squashfs. squashfs_bdi_init will set - * sb->s_bdi->ra_pages and sb->s_bdi->io_pages to 0 and close readahead for - * squashfs. - */ - err = squashfs_bdi_init(sb); - if (err) { - errorf(fc, "squashfs init bdi failed"); - return err; - } - sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL); if (sb->s_fs_info == NULL) { ERROR("Failed to allocate squashfs_sb_info\n"); -- 2.7.4