Commit 1dfff7dd authored by Kees Cook's avatar Kees Cook

pstore: Pass record contents instead of copying

pstore_mkfile() shouldn't have to memcpy the record contents. It can use
the existing copy instead. This adjusts the allocation lifetime management
and renames the contents variable from "data" to "buf" to assist moving to
struct pstore_record in the future.
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 7e8cc8dc
...@@ -52,7 +52,7 @@ struct pstore_private { ...@@ -52,7 +52,7 @@ struct pstore_private {
u64 id; u64 id;
int count; int count;
ssize_t size; ssize_t size;
char data[]; char *buf;
}; };
struct pstore_ftrace_seq_data { struct pstore_ftrace_seq_data {
...@@ -63,6 +63,14 @@ struct pstore_ftrace_seq_data { ...@@ -63,6 +63,14 @@ struct pstore_ftrace_seq_data {
#define REC_SIZE sizeof(struct pstore_ftrace_record) #define REC_SIZE sizeof(struct pstore_ftrace_record)
static void free_pstore_private(struct pstore_private *private)
{
if (!private)
return;
kfree(private->buf);
kfree(private);
}
static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
{ {
struct pstore_private *ps = s->private; struct pstore_private *ps = s->private;
...@@ -105,7 +113,7 @@ static int pstore_ftrace_seq_show(struct seq_file *s, void *v) ...@@ -105,7 +113,7 @@ static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
{ {
struct pstore_private *ps = s->private; struct pstore_private *ps = s->private;
struct pstore_ftrace_seq_data *data = v; struct pstore_ftrace_seq_data *data = v;
struct pstore_ftrace_record *rec = (void *)(ps->data + data->off); struct pstore_ftrace_record *rec = (void *)(ps->buf + data->off);
seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n", seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
pstore_ftrace_decode_cpu(rec), pstore_ftrace_decode_cpu(rec),
...@@ -143,7 +151,7 @@ static ssize_t pstore_file_read(struct file *file, char __user *userbuf, ...@@ -143,7 +151,7 @@ static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
if (ps->type == PSTORE_TYPE_FTRACE) if (ps->type == PSTORE_TYPE_FTRACE)
return seq_read(file, userbuf, count, ppos); return seq_read(file, userbuf, count, ppos);
return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); return simple_read_from_buffer(userbuf, count, ppos, ps->buf, ps->size);
} }
static int pstore_file_open(struct inode *inode, struct file *file) static int pstore_file_open(struct inode *inode, struct file *file)
...@@ -221,7 +229,7 @@ static void pstore_evict_inode(struct inode *inode) ...@@ -221,7 +229,7 @@ static void pstore_evict_inode(struct inode *inode)
spin_lock_irqsave(&allpstore_lock, flags); spin_lock_irqsave(&allpstore_lock, flags);
list_del(&p->list); list_del(&p->list);
spin_unlock_irqrestore(&allpstore_lock, flags); spin_unlock_irqrestore(&allpstore_lock, flags);
kfree(p); free_pstore_private(p);
} }
} }
...@@ -332,7 +340,7 @@ int pstore_mkfile(struct pstore_record *record) ...@@ -332,7 +340,7 @@ int pstore_mkfile(struct pstore_record *record)
goto fail; goto fail;
inode->i_mode = S_IFREG | 0444; inode->i_mode = S_IFREG | 0444;
inode->i_fop = &pstore_file_operations; inode->i_fop = &pstore_file_operations;
private = kmalloc(sizeof *private + size, GFP_KERNEL); private = kzalloc(sizeof(*private), GFP_KERNEL);
if (!private) if (!private)
goto fail_alloc; goto fail_alloc;
private->type = record->type; private->type = record->type;
...@@ -394,7 +402,7 @@ int pstore_mkfile(struct pstore_record *record) ...@@ -394,7 +402,7 @@ int pstore_mkfile(struct pstore_record *record)
if (!dentry) if (!dentry)
goto fail_lockedalloc; goto fail_lockedalloc;
memcpy(private->data, record->buf, size); private->buf = record->buf;
inode->i_size = private->size = size; inode->i_size = private->size = size;
inode->i_private = private; inode->i_private = private;
...@@ -414,7 +422,7 @@ int pstore_mkfile(struct pstore_record *record) ...@@ -414,7 +422,7 @@ int pstore_mkfile(struct pstore_record *record)
fail_lockedalloc: fail_lockedalloc:
inode_unlock(d_inode(root)); inode_unlock(d_inode(root));
kfree(private); free_pstore_private(private);
fail_alloc: fail_alloc:
iput(inode); iput(inode);
......
...@@ -828,14 +828,22 @@ void pstore_get_records(int quiet) ...@@ -828,14 +828,22 @@ void pstore_get_records(int quiet)
if (psi->open && psi->open(psi)) if (psi->open && psi->open(psi))
goto out; goto out;
/*
* Backend callback read() allocates record.buf. decompress_record()
* may reallocate record.buf. On success, pstore_mkfile() will keep
* the record.buf, so free it only on failure.
*/
while ((record.size = psi->read(&record)) > 0) { while ((record.size = psi->read(&record)) > 0) {
decompress_record(&record); decompress_record(&record);
rc = pstore_mkfile(&record); rc = pstore_mkfile(&record);
if (rc) {
if (rc && (rc != -EEXIST || !quiet)) /* pstore_mkfile() did not take buf, so free it. */
kfree(record.buf);
if (rc != -EEXIST || !quiet)
failed++; failed++;
}
kfree(record.buf); /* Reset for next record. */
memset(&record, 0, sizeof(record)); memset(&record, 0, sizeof(record));
record.psi = psi; record.psi = psi;
} }
......
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