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authorMark Salyzyn <salyzyn@android.com>2016-09-01 08:13:46 -0700
committerKees Cook <keescook@chromium.org>2016-09-08 15:01:10 -0700
commit5bf6d1b92715f224ef6e1c3abca5dd63eeb4915d (patch)
tree09139364ae61fbb0b188c0a762861bf800b70d23 /fs/pstore/ram_core.c
parent79d955af711a6e20207783590a2cfddbd649568b (diff)
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pstore/pmsg: drop bounce buffer
Removing a bounce buffer copy operation in the pmsg driver path is always better. We also gain in overall performance by not requesting a vmalloc on every write as this can cause precious RT tasks, such as user facing media operation, to stall while memory is being reclaimed. Added a write_buf_user to the pstore functions, a backup platform write_buf_user that uses the small buffer that is part of the instance, and implemented a ramoops write_buf_user that only supports PSTORE_TYPE_PMSG. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/pstore/ram_core.c')
-rw-r--r--fs/pstore/ram_core.c47
1 files changed, 45 insertions, 2 deletions
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 9cc6efe0b785..9486c4873c69 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -17,15 +17,16 @@
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
-#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
+#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/memblock.h>
+#include <linux/pstore_ram.h>
#include <linux/rslib.h>
#include <linux/slab.h>
+#include <linux/uaccess.h>
#include <linux/vmalloc.h>
-#include <linux/pstore_ram.h>
#include <asm/page.h>
struct persistent_ram_buffer {
@@ -267,6 +268,16 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
persistent_ram_update_ecc(prz, start, count);
}
+static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
+ const void __user *s, unsigned int start, unsigned int count)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
+ -EFAULT : 0;
+ persistent_ram_update_ecc(prz, start, count);
+ return ret;
+}
+
void persistent_ram_save_old(struct persistent_ram_zone *prz)
{
struct persistent_ram_buffer *buffer = prz->buffer;
@@ -320,6 +331,38 @@ int notrace persistent_ram_write(struct persistent_ram_zone *prz,
return count;
}
+int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
+ const void __user *s, unsigned int count)
+{
+ int rem, ret = 0, c = count;
+ size_t start;
+
+ if (unlikely(!access_ok(VERIFY_READ, s, count)))
+ return -EFAULT;
+ if (unlikely(c > prz->buffer_size)) {
+ s += c - prz->buffer_size;
+ c = prz->buffer_size;
+ }
+
+ buffer_size_add(prz, c);
+
+ start = buffer_start_add(prz, c);
+
+ rem = prz->buffer_size - start;
+ if (unlikely(rem < c)) {
+ ret = persistent_ram_update_user(prz, s, start, rem);
+ s += rem;
+ c -= rem;
+ start = 0;
+ }
+ if (likely(!ret))
+ ret = persistent_ram_update_user(prz, s, start, c);
+
+ persistent_ram_update_header_ecc(prz);
+
+ return unlikely(ret) ? ret : count;
+}
+
size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
{
return prz->old_log_size;