2b51d006cd
It's not a common practice to use the same io function for both read and write (we have pread() and pwrite(), not pio()). Furthermore the original function has the following problems: - Not returning proper error number If we had ioctl/stat errors we just return 0 with errno set. Thus caller would treat it as a short read, not a proper error. - Unnecessary @ret_rw This is not that obvious if we have different handling for read and write, but if we split them it's super obvious we can reuse @ret. - No proper copy back for short read - Unable to constify the @buf pointer for write operation All those problems would be addressed in this patch. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
81 lines
2.6 KiB
C
81 lines
2.6 KiB
C
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __DEVICE_UTILS_H__
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#define __DEVICE_UTILS_H__
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#include "kerncompat.h"
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#include <sys/stat.h>
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#include <stdbool.h>
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#include <unistd.h>
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/*
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* Options for btrfs_prepare_device
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*/
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#define PREP_DEVICE_ZERO_END (1U << 0)
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#define PREP_DEVICE_DISCARD (1U << 1)
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#define PREP_DEVICE_VERBOSE (1U << 2)
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#define PREP_DEVICE_ZONED (1U << 3)
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/* Placeholder to denote no results for the zone_unusable sysfs value */
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#define DEVICE_ZONE_UNUSABLE_UNKNOWN ((u64)-1)
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/*
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* Generic block device helpers
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*/
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int device_discard_blocks(int fd, u64 start, u64 len);
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int device_zero_blocks(int fd, off_t start, size_t len, const bool direct);
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u64 device_get_partition_size(const char *dev);
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u64 device_get_partition_size_fd(int fd);
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u64 device_get_partition_size_fd_stat(int fd, const struct stat *st);
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int device_get_queue_param(const char *file, const char *param, char *buf, size_t len);
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u64 device_get_zone_unusable(int fd, u64 flags);
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u64 device_get_zone_size(int fd, const char *name);
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int device_get_rotational(const char *file);
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/*
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* Updates to devices with btrfs-specific changs
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*/
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int btrfs_prepare_device(int fd, const char *file, u64 *block_count_ret,
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u64 max_block_count, unsigned opflags);
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ssize_t btrfs_direct_pread(int fd, void *buf, size_t count, off_t offset);
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ssize_t btrfs_direct_pwrite(int fd, const void *buf, size_t count, off_t offset);
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#ifdef BTRFS_ZONED
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static inline ssize_t btrfs_pwrite(int fd, void *buf, size_t count,
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off_t offset, bool direct)
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{
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if (!direct)
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return pwrite(fd, buf, count, offset);
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return btrfs_direct_pwrite(fd, buf, count, offset);
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}
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static inline ssize_t btrfs_pread(int fd, void *buf, size_t count, off_t offset,
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bool direct)
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{
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if (!direct)
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return pread(fd, buf, count, offset);
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return btrfs_direct_pread(fd, buf, count, offset);
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}
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#else
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#define btrfs_pwrite(fd, buf, count, offset, direct) \
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({ (void)(direct); pwrite(fd, buf, count, offset); })
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#define btrfs_pread(fd, buf, count, offset, direct) \
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({ (void)(direct); pread(fd, buf, count, offset); })
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#endif
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#endif
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