From 41da51bce36f44eefc1e3d0f47d18841cbd065ba Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 21 Nov 2019 23:25:07 +0000 Subject: fs: Add IOCB_NOIO flag for generic_file_read_iter Add an IOCB_NOIO flag that indicates to generic_file_read_iter that it shouldn't trigger any filesystem I/O for the actual request or for readahead. This allows to do tentative reads out of the page cache as some filesystems allow, and to take the appropriate locks and retry the reads only if the requested pages are not cached. Signed-off-by: Andreas Gruenbacher --- include/linux/fs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 3f881a892ea7..4b7cb76e5837 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -315,6 +315,7 @@ enum rw_hint { #define IOCB_SYNC (1 << 5) #define IOCB_WRITE (1 << 6) #define IOCB_NOWAIT (1 << 7) +#define IOCB_NOIO (1 << 9) struct kiocb { struct file *ki_filp; -- cgit v1.2.3-71-gd317 From 61a707c543e2afe3aa7e88f87267c5dafa4b5afa Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 8 May 2020 08:54:16 +0200 Subject: fs: add a __kernel_read helper This is the counterpart to __kernel_write, and skip the rw_verify_area call compared to kernel_read. Signed-off-by: Christoph Hellwig --- fs/read_write.c | 23 +++++++++++++++++++++++ include/linux/fs.h | 1 + 2 files changed, 24 insertions(+) (limited to 'include/linux/fs.h') diff --git a/fs/read_write.c b/fs/read_write.c index 96e8e354f99b..21c9d90a257e 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -430,6 +430,29 @@ ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, return -EINVAL; } +ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) +{ + mm_segment_t old_fs = get_fs(); + ssize_t ret; + + if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ))) + return -EINVAL; + if (!(file->f_mode & FMODE_CAN_READ)) + return -EINVAL; + + if (count > MAX_RW_COUNT) + count = MAX_RW_COUNT; + set_fs(KERNEL_DS); + ret = __vfs_read(file, (void __user *)buf, count, pos); + set_fs(old_fs); + if (ret > 0) { + fsnotify_access(file); + add_rchar(current, ret); + } + inc_syscr(current); + return ret; +} + ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; diff --git a/include/linux/fs.h b/include/linux/fs.h index 3f881a892ea7..22cbe7b2e919 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3033,6 +3033,7 @@ extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, lo extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t, enum kernel_read_file_id); extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *); +ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos); extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *); extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *); extern struct file * open_exec(const char *); -- cgit v1.2.3-71-gd317 From 775802c0571fb438cd4f6548a323f9e4cb89f5aa Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 8 May 2020 11:17:46 +0200 Subject: fs: remove __vfs_read Fold it into the two callers. Signed-off-by: Christoph Hellwig --- fs/read_write.c | 43 +++++++++++++++++++++---------------------- include/linux/fs.h | 1 - 2 files changed, 21 insertions(+), 23 deletions(-) (limited to 'include/linux/fs.h') diff --git a/fs/read_write.c b/fs/read_write.c index 42a027719324..4fb797822567 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -419,17 +419,6 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo return ret; } -ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, - loff_t *pos) -{ - if (file->f_op->read) - return file->f_op->read(file, buf, count, pos); - else if (file->f_op->read_iter) - return new_sync_read(file, buf, count, pos); - else - return -EINVAL; -} - ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { mm_segment_t old_fs = get_fs(); @@ -443,7 +432,12 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; set_fs(KERNEL_DS); - ret = __vfs_read(file, (void __user *)buf, count, pos); + if (file->f_op->read) + ret = file->f_op->read(file, (void __user *)buf, count, pos); + else if (file->f_op->read_iter) + ret = new_sync_read(file, (void __user *)buf, count, pos); + else + ret = -EINVAL; set_fs(old_fs); if (ret > 0) { fsnotify_access(file); @@ -476,17 +470,22 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) return -EFAULT; ret = rw_verify_area(READ, file, pos, count); - if (!ret) { - if (count > MAX_RW_COUNT) - count = MAX_RW_COUNT; - ret = __vfs_read(file, buf, count, pos); - if (ret > 0) { - fsnotify_access(file); - add_rchar(current, ret); - } - inc_syscr(current); - } + if (ret) + return ret; + if (count > MAX_RW_COUNT) + count = MAX_RW_COUNT; + if (file->f_op->read) + ret = file->f_op->read(file, buf, count, pos); + else if (file->f_op->read_iter) + ret = new_sync_read(file, buf, count, pos); + else + ret = -EINVAL; + if (ret > 0) { + fsnotify_access(file); + add_rchar(current, ret); + } + inc_syscr(current); return ret; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 22cbe7b2e919..0c0ec76b600b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1917,7 +1917,6 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, struct iovec *fast_pointer, struct iovec **ret_pointer); -extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *); extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *); extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *); extern ssize_t vfs_readv(struct file *, const struct iovec __user *, -- cgit v1.2.3-71-gd317