Revision a0cff57bb2a41cb9cbf13d3203097b4156d8c0ae authored by Davidlohr Bueso on 13 September 2017, 20:08:21 UTC, committed by Paolo Bonzini on 15 September 2017, 14:57:12 UTC
During code inspection, the following potential race was seen: CPU0 CPU1 kvm_async_pf_task_wait apf_task_wake_one [L] swait_active(&n->wq) [S] prepare_to_swait(&n.wq) [L] if (!hlist_unhahed(&n.link)) schedule() [S] hlist_del_init(&n->link); Properly serialize swait_active() checks such that a wakeup is not missed. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent cc1b468
io.c
/*
* linux/fs/befs/io.c
*
* Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
*
* Based on portions of file.c and inode.c
* by Makoto Kato (m_kato@ga2.so-net.ne.jp)
*
* Many thanks to Dominic Giampaolo, author of Practical File System
* Design with the Be File System, for such a helpful book.
*
*/
#include <linux/buffer_head.h>
#include "befs.h"
#include "io.h"
/*
* Converts befs notion of disk addr to a disk offset and uses
* linux kernel function sb_bread() to get the buffer containing
* the offset.
*/
struct buffer_head *
befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
{
struct buffer_head *bh;
befs_blocknr_t block;
struct befs_sb_info *befs_sb = BEFS_SB(sb);
befs_debug(sb, "---> Enter %s "
"[%u, %hu, %hu]", __func__, iaddr.allocation_group,
iaddr.start, iaddr.len);
if (iaddr.allocation_group > befs_sb->num_ags) {
befs_error(sb, "BEFS: Invalid allocation group %u, max is %u",
iaddr.allocation_group, befs_sb->num_ags);
goto error;
}
block = iaddr2blockno(sb, &iaddr);
befs_debug(sb, "%s: offset = %lu", __func__, (unsigned long)block);
bh = sb_bread(sb, block);
if (bh == NULL) {
befs_error(sb, "Failed to read block %lu",
(unsigned long)block);
goto error;
}
befs_debug(sb, "<--- %s", __func__);
return bh;
error:
befs_debug(sb, "<--- %s ERROR", __func__);
return NULL;
}
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