[PATCH 18/18] pstore: Remove write_buf() callback
Kees Cook
keescook at chromium.org
Tue Mar 7 08:55:32 AEDT 2017
Now that write() and write_buf() are functionally identical, this removes
write_buf(), and renames write_buf_user() to write_user(). Additionally
adds sanity-checks for pstore_info's declared functions and flags at
registration time.
Signed-off-by: Kees Cook <keescook at chromium.org>
---
fs/pstore/ftrace.c | 4 ++--
fs/pstore/platform.c | 35 ++++++++++++++++++++---------------
fs/pstore/pmsg.c | 4 ++--
fs/pstore/ram.c | 10 +++++-----
include/linux/pstore.h | 29 ++++++++++-------------------
5 files changed, 39 insertions(+), 43 deletions(-)
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index a5506ec6995e..06aab07b6bb7 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -53,7 +53,7 @@ static void notrace pstore_ftrace_call(unsigned long ip,
rec.parent_ip = parent_ip;
pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
- psinfo->write_buf(&record);
+ psinfo->write(&record);
local_irq_restore(flags);
}
@@ -122,7 +122,7 @@ void pstore_register_ftrace(void)
{
struct dentry *file;
- if (!psinfo->write_buf)
+ if (!psinfo->write)
return;
pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 1e6642a2063e..e79f170fa79b 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -604,7 +604,7 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
}
record.buf = (char *)s;
record.size = c;
- psinfo->write_buf(&record);
+ psinfo->write(&record);
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
s += c;
c = e - s;
@@ -632,15 +632,8 @@ static void pstore_register_console(void) {}
static void pstore_unregister_console(void) {}
#endif
-static int pstore_write_compat(struct pstore_record *record)
-{
- record->buf = psinfo->buf;
-
- return record->psi->write_buf(record);
-}
-
-static int pstore_write_buf_user_compat(struct pstore_record *record,
- const char __user *buf)
+static int pstore_write_user_compat(struct pstore_record *record,
+ const char __user *buf)
{
unsigned long flags = 0;
size_t i, bufsize, total_size = record->size;
@@ -662,7 +655,7 @@ static int pstore_write_buf_user_compat(struct pstore_record *record,
break;
}
record->size = c;
- ret = record->psi->write_buf(record);
+ ret = record->psi->write(record);
if (unlikely(ret < 0))
break;
i += c;
@@ -687,6 +680,20 @@ int pstore_register(struct pstore_info *psi)
return -EPERM;
}
+ /* Sanity check flags. */
+ if (!psi->flags) {
+ pr_warn("backend '%s' must support at least one frontend\n",
+ psi->name);
+ return -EINVAL;
+ }
+
+ /* Check for required functions. */
+ if (!psi->read || !psi->write) {
+ pr_warn("backend '%s' must implement read() and write()\n",
+ psi->name);
+ return -EINVAL;
+ }
+
spin_lock(&pstore_lock);
if (psinfo) {
pr_warn("backend '%s' already loaded: ignoring '%s'\n",
@@ -695,10 +702,8 @@ int pstore_register(struct pstore_info *psi)
return -EBUSY;
}
- if (!psi->write)
- psi->write = pstore_write_compat;
- if (!psi->write_buf_user)
- psi->write_buf_user = pstore_write_buf_user_compat;
+ if (!psi->write_user)
+ psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);
diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c
index ce35907602de..c16a2477e106 100644
--- a/fs/pstore/pmsg.c
+++ b/fs/pstore/pmsg.c
@@ -33,12 +33,12 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf,
if (!count)
return 0;
- /* check outside lock, page in any data. write_buf_user also checks */
+ /* check outside lock, page in any data. write_user also checks */
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
mutex_lock(&pmsg_lock);
- ret = psinfo->write_buf_user(&record, buf);
+ ret = psinfo->write_user(&record, buf);
mutex_unlock(&pmsg_lock);
return ret ? ret : count;
}
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index d85e1adae1b6..5523df7f17ef 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -378,7 +378,7 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
return len;
}
-static int notrace ramoops_pstore_write_buf(struct pstore_record *record)
+static int notrace ramoops_pstore_write(struct pstore_record *record)
{
struct ramoops_context *cxt = record->psi->data;
struct persistent_ram_zone *prz;
@@ -451,8 +451,8 @@ static int notrace ramoops_pstore_write_buf(struct pstore_record *record)
return 0;
}
-static int notrace ramoops_pstore_write_buf_user(struct pstore_record *record,
- const char __user *buf)
+static int notrace ramoops_pstore_write_user(struct pstore_record *record,
+ const char __user *buf)
{
if (record->type == PSTORE_TYPE_PMSG) {
struct ramoops_context *cxt = record->psi->data;
@@ -503,8 +503,8 @@ static struct ramoops_context oops_cxt = {
.name = "ramoops",
.open = ramoops_pstore_open,
.read = ramoops_pstore_read,
- .write_buf = ramoops_pstore_write_buf,
- .write_buf_user = ramoops_pstore_write_buf_user,
+ .write = ramoops_pstore_write,
+ .write_user = ramoops_pstore_write_user,
.erase = ramoops_pstore_erase,
},
};
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 7f6eaa71504e..936744221171 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -130,27 +130,19 @@ struct pstore_record {
* available, or negative on error.
*
* @write:
- * Perform a frontend notification of a write to a backend record. The
- * data to be stored has already been written to the registered @buf
- * of the @psi structure.
+ * A newly generated record needs to be written to backend storage.
*
* @record:
- * pointer to record metadata. Note that @buf is NULL, since
- * the @buf registered with @psi is what has been written. The
- * backend is expected to update @id.
+ * pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
+ * @buf will be pointing to the preallocated @psi.buf, since
+ * memory allocation may be broken during an Oops. Regardless,
+ * @buf must be proccesed or copied before returning. The
+ * backend is also expected to write @id with something that
+ 8 can help identify this record to a future @erase callback.
*
* Returns 0 on success, and non-zero on error.
*
- * @write_buf:
- * Perform a frontend write to a backend record. The record contains
- * all metadata and the buffer to write to backend storage. (Unlike
- * @write, this does not use the @psi @buf.)
- *
- * @record: pointer to record metadata.
- *
- * Returns 0 on success, and non-zero on error.
- *
- * @write_buf_user:
+ * @write_user:
* Perform a frontend write to a backend record, using a specified
* buffer that is coming directly from userspace, instead of the
* @record @buf.
@@ -188,9 +180,8 @@ struct pstore_info {
int (*close)(struct pstore_info *psi);
ssize_t (*read)(struct pstore_record *record);
int (*write)(struct pstore_record *record);
- int (*write_buf)(struct pstore_record *record);
- int (*write_buf_user)(struct pstore_record *record,
- const char __user *buf);
+ int (*write_user)(struct pstore_record *record,
+ const char __user *buf);
int (*erase)(struct pstore_record *record);
};
--
2.7.4
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