[PATCH 06/10] staging: lustre: llite: use more private data in dump_pgcache

From: NeilBrown
Date: Sun May 06 2018 - 20:56:16 EST


The dump_page_cache debugfs file allocates and frees an 'env' in each
call to vvp_pgcache_start,next,show. This is likely to be fast, but
does introduce the need to check for errors.

It is reasonable to allocate a single 'env' when the file is opened,
and use that throughout.

So create 'seq_private' structure which stores the sbi, env, and
refcheck, and attach this to the seqfile.

Then use it throughout instead of allocating 'env' repeatedly.

Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
drivers/staging/lustre/lustre/llite/vvp_dev.c | 148 ++++++++++++-------------
1 file changed, 72 insertions(+), 76 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/vvp_dev.c b/drivers/staging/lustre/lustre/llite/vvp_dev.c
index 987c03b058e6..183ea3d0f336 100644
--- a/drivers/staging/lustre/lustre/llite/vvp_dev.c
+++ b/drivers/staging/lustre/lustre/llite/vvp_dev.c
@@ -390,6 +390,12 @@ struct vvp_pgcache_id {
struct lu_object_header *vpi_obj;
};

+struct seq_private {
+ struct ll_sb_info *sbi;
+ struct lu_env *env;
+ u16 refcheck;
+};
+
static void vvp_pgcache_id_unpack(loff_t pos, struct vvp_pgcache_id *id)
{
BUILD_BUG_ON(sizeof(pos) != sizeof(__u64));
@@ -531,95 +537,72 @@ static void vvp_pgcache_page_show(const struct lu_env *env,

static int vvp_pgcache_show(struct seq_file *f, void *v)
{
+ struct seq_private *priv = f->private;
loff_t pos;
- struct ll_sb_info *sbi;
struct cl_object *clob;
- struct lu_env *env;
struct vvp_pgcache_id id;
- u16 refcheck;
- int result;

- env = cl_env_get(&refcheck);
- if (!IS_ERR(env)) {
- pos = *(loff_t *)v;
- vvp_pgcache_id_unpack(pos, &id);
- sbi = f->private;
- clob = vvp_pgcache_obj(env, &sbi->ll_cl->cd_lu_dev, &id);
- if (clob) {
- struct inode *inode = vvp_object_inode(clob);
- struct cl_page *page = NULL;
- struct page *vmpage;
-
- result = find_get_pages_contig(inode->i_mapping,
- id.vpi_index, 1,
- &vmpage);
- if (result > 0) {
- lock_page(vmpage);
- page = cl_vmpage_page(vmpage, clob);
- unlock_page(vmpage);
- put_page(vmpage);
- }
+ pos = *(loff_t *)v;
+ vvp_pgcache_id_unpack(pos, &id);
+ clob = vvp_pgcache_obj(priv->env, &priv->sbi->ll_cl->cd_lu_dev, &id);
+ if (clob) {
+ struct inode *inode = vvp_object_inode(clob);
+ struct cl_page *page = NULL;
+ struct page *vmpage;
+ int result;
+
+ result = find_get_pages_contig(inode->i_mapping,
+ id.vpi_index, 1,
+ &vmpage);
+ if (result > 0) {
+ lock_page(vmpage);
+ page = cl_vmpage_page(vmpage, clob);
+ unlock_page(vmpage);
+ put_page(vmpage);
+ }

- seq_printf(f, "%8x@" DFID ": ", id.vpi_index,
- PFID(lu_object_fid(&clob->co_lu)));
- if (page) {
- vvp_pgcache_page_show(env, f, page);
- cl_page_put(env, page);
- } else {
- seq_puts(f, "missing\n");
- }
- lu_object_ref_del(&clob->co_lu, "dump", current);
- cl_object_put(env, clob);
+ seq_printf(f, "%8x@" DFID ": ", id.vpi_index,
+ PFID(lu_object_fid(&clob->co_lu)));
+ if (page) {
+ vvp_pgcache_page_show(priv->env, f, page);
+ cl_page_put(priv->env, page);
} else {
- seq_printf(f, "%llx missing\n", pos);
+ seq_puts(f, "missing\n");
}
- cl_env_put(env, &refcheck);
- result = 0;
+ lu_object_ref_del(&clob->co_lu, "dump", current);
+ cl_object_put(priv->env, clob);
} else {
- result = PTR_ERR(env);
+ seq_printf(f, "%llx missing\n", pos);
}
- return result;
+ return 0;
}

static void *vvp_pgcache_start(struct seq_file *f, loff_t *pos)
{
- struct ll_sb_info *sbi;
- struct lu_env *env;
- u16 refcheck;
-
- sbi = f->private;
+ struct seq_private *priv = f->private;

- env = cl_env_get(&refcheck);
- if (!IS_ERR(env)) {
- sbi = f->private;
- if (sbi->ll_site->ls_obj_hash->hs_cur_bits >
- 64 - PGC_OBJ_SHIFT) {
- pos = ERR_PTR(-EFBIG);
- } else {
- *pos = vvp_pgcache_find(env, &sbi->ll_cl->cd_lu_dev,
- *pos);
- if (*pos == ~0ULL)
- pos = NULL;
- }
- cl_env_put(env, &refcheck);
+ if (priv->sbi->ll_site->ls_obj_hash->hs_cur_bits >
+ 64 - PGC_OBJ_SHIFT) {
+ pos = ERR_PTR(-EFBIG);
+ } else {
+ *pos = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
+ *pos);
+ if (*pos == ~0ULL)
+ pos = NULL;
}
+
return pos;
}

static void *vvp_pgcache_next(struct seq_file *f, void *v, loff_t *pos)
{
- struct ll_sb_info *sbi;
- struct lu_env *env;
- u16 refcheck;
+ struct seq_private *priv = f->private;
+
+ *pos = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
+ *pos + 1);
+ if (*pos == ~0ULL)
+ pos = NULL;

- env = cl_env_get(&refcheck);
- if (!IS_ERR(env)) {
- sbi = f->private;
- *pos = vvp_pgcache_find(env, &sbi->ll_cl->cd_lu_dev, *pos + 1);
- if (*pos == ~0ULL)
- pos = NULL;
- cl_env_put(env, &refcheck);
- }
return pos;
}

@@ -637,23 +620,36 @@ static const struct seq_operations vvp_pgcache_ops = {

static int vvp_dump_pgcache_seq_open(struct inode *inode, struct file *filp)
{
- struct seq_file *seq;
- int rc;
+ struct seq_private *priv;

- rc = seq_open(filp, &vvp_pgcache_ops);
- if (rc)
- return rc;
+ priv = __seq_open_private(filp, &vvp_pgcache_ops, sizeof(*priv));
+ if (!priv)
+ return -ENOMEM;

- seq = filp->private_data;
- seq->private = inode->i_private;
+ priv->sbi = inode->i_private;
+ priv->env = cl_env_get(&priv->refcheck);
+ if (IS_ERR(priv->env)) {
+ int err = PTR_ERR(priv->env);

+ seq_release_private(inode, filp);
+ return err;
+ }
return 0;
}

+static int vvp_dump_pgcache_seq_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct seq_private *priv = seq->private;
+
+ cl_env_put(priv->env, &priv->refcheck);
+ return seq_release_private(inode, file);
+}
+
const struct file_operations vvp_dump_pgcache_file_ops = {
.owner = THIS_MODULE,
.open = vvp_dump_pgcache_seq_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = vvp_dump_pgcache_seq_release,
};