6.6-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro viro@zeniv.linux.org.uk
[ Upstream commit c134deabf4784e155d360744d4a6a835b9de4dd4 ]
prior to "[POWERPC] spufs: Fix gang destroy leaks" we used to have a problem with gang lifetimes - creation of a gang returns opened gang directory, which normally gets removed when that gets closed, but if somebody has created a context belonging to that gang and kept it alive until the gang got closed, removal failed and we ended up with a leak.
Unfortunately, it had been fixed the wrong way. Dentry of gang directory was no longer pinned, and rmdir on close was gone. One problem was that failure of open kept calling simple_rmdir() as cleanup, which meant an unbalanced dput(). Another bug was in the success case - gang creation incremented link count on root directory, but that was no longer undone when gang got destroyed.
Fix consists of * reverting the commit in question * adding a counter to gang, protected by ->i_rwsem of gang directory inode. * having it set to 1 at creation time, dropped in both spufs_dir_close() and spufs_gang_close() and bumped in spufs_create_context(), provided that it's not 0. * using simple_recursive_removal() to take the gang directory out when counter reaches zero.
Fixes: 877907d37da9 "[POWERPC] spufs: Fix gang destroy leaks" Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/platforms/cell/spufs/gang.c | 1 + arch/powerpc/platforms/cell/spufs/inode.c | 54 +++++++++++++++++++---- arch/powerpc/platforms/cell/spufs/spufs.h | 2 + 3 files changed, 49 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/platforms/cell/spufs/gang.c b/arch/powerpc/platforms/cell/spufs/gang.c index 827d338deaf4c..2c2999de6bfa2 100644 --- a/arch/powerpc/platforms/cell/spufs/gang.c +++ b/arch/powerpc/platforms/cell/spufs/gang.c @@ -25,6 +25,7 @@ struct spu_gang *alloc_spu_gang(void) mutex_init(&gang->aff_mutex); INIT_LIST_HEAD(&gang->list); INIT_LIST_HEAD(&gang->aff_list_head); + gang->alive = 1;
out: return gang; diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c index 8acefe5f654c9..a0f297581a66c 100644 --- a/arch/powerpc/platforms/cell/spufs/inode.c +++ b/arch/powerpc/platforms/cell/spufs/inode.c @@ -200,6 +200,23 @@ static int spufs_fill_dir(struct dentry *dir, return 0; }
+static void unuse_gang(struct dentry *dir) +{ + struct inode *inode = dir->d_inode; + struct spu_gang *gang = SPUFS_I(inode)->i_gang; + + if (gang) { + bool dead; + + inode_lock(inode); // exclusion with spufs_create_context() + dead = !--gang->alive; + inode_unlock(inode); + + if (dead) + simple_recursive_removal(dir, NULL); + } +} + static int spufs_dir_close(struct inode *inode, struct file *file) { struct inode *parent; @@ -214,6 +231,7 @@ static int spufs_dir_close(struct inode *inode, struct file *file) inode_unlock(parent); WARN_ON(ret);
+ unuse_gang(dir->d_parent); return dcache_dir_close(inode, file); }
@@ -406,7 +424,7 @@ spufs_create_context(struct inode *inode, struct dentry *dentry, { int ret; int affinity; - struct spu_gang *gang; + struct spu_gang *gang = SPUFS_I(inode)->i_gang; struct spu_context *neighbor; struct path path = {.mnt = mnt, .dentry = dentry};
@@ -421,11 +439,15 @@ spufs_create_context(struct inode *inode, struct dentry *dentry, if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader) return -ENODEV;
- gang = NULL; + if (gang) { + if (!gang->alive) + return -ENOENT; + gang->alive++; + } + neighbor = NULL; affinity = flags & (SPU_CREATE_AFFINITY_MEM | SPU_CREATE_AFFINITY_SPU); if (affinity) { - gang = SPUFS_I(inode)->i_gang; if (!gang) return -EINVAL; mutex_lock(&gang->aff_mutex); @@ -454,6 +476,8 @@ spufs_create_context(struct inode *inode, struct dentry *dentry, out_aff_unlock: if (affinity) mutex_unlock(&gang->aff_mutex); + if (ret && gang) + gang->alive--; // can't reach 0 return ret; }
@@ -483,6 +507,7 @@ spufs_mkgang(struct inode *dir, struct dentry *dentry, umode_t mode) inode->i_fop = &simple_dir_operations;
d_instantiate(dentry, inode); + dget(dentry); inc_nlink(dir); inc_nlink(d_inode(dentry)); return ret; @@ -493,6 +518,21 @@ spufs_mkgang(struct inode *dir, struct dentry *dentry, umode_t mode) return ret; }
+static int spufs_gang_close(struct inode *inode, struct file *file) +{ + unuse_gang(file->f_path.dentry); + return dcache_dir_close(inode, file); +} + +static const struct file_operations spufs_gang_fops = { + .open = dcache_dir_open, + .release = spufs_gang_close, + .llseek = dcache_dir_lseek, + .read = generic_read_dir, + .iterate_shared = dcache_readdir, + .fsync = noop_fsync, +}; + static int spufs_gang_open(const struct path *path) { int ret; @@ -512,7 +552,7 @@ static int spufs_gang_open(const struct path *path) return PTR_ERR(filp); }
- filp->f_op = &simple_dir_operations; + filp->f_op = &spufs_gang_fops; fd_install(ret, filp); return ret; } @@ -527,10 +567,8 @@ static int spufs_create_gang(struct inode *inode, ret = spufs_mkgang(inode, dentry, mode & 0777); if (!ret) { ret = spufs_gang_open(&path); - if (ret < 0) { - int err = simple_rmdir(inode, dentry); - WARN_ON(err); - } + if (ret < 0) + unuse_gang(dentry); } return ret; } diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h index 84958487f696a..d33787c57c39a 100644 --- a/arch/powerpc/platforms/cell/spufs/spufs.h +++ b/arch/powerpc/platforms/cell/spufs/spufs.h @@ -151,6 +151,8 @@ struct spu_gang { int aff_flags; struct spu *aff_ref_spu; atomic_t aff_sched_count; + + int alive; };
/* Flag bits for spu_gang aff_flags */