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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/platform.c
parent79d955af711a6e20207783590a2cfddbd649568b (diff)
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/platform.c')
-rw-r--r--fs/pstore/platform.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 76dd604a0f2c..14984d902a99 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -623,6 +623,40 @@ static int pstore_write_compat(enum pstore_type_id type,
size, psi);
}
+static int pstore_write_buf_user_compat(enum pstore_type_id type,
+ enum kmsg_dump_reason reason,
+ u64 *id, unsigned int part,
+ const char __user *buf,
+ bool compressed, size_t size,
+ struct pstore_info *psi)
+{
+ unsigned long flags = 0;
+ size_t i, bufsize = size;
+ long ret = 0;
+
+ if (unlikely(!access_ok(VERIFY_READ, buf, size)))
+ return -EFAULT;
+ if (bufsize > psinfo->bufsize)
+ bufsize = psinfo->bufsize;
+ spin_lock_irqsave(&psinfo->buf_lock, flags);
+ for (i = 0; i < size; ) {
+ size_t c = min(size - i, bufsize);
+
+ ret = __copy_from_user(psinfo->buf, buf + i, c);
+ if (unlikely(ret != 0)) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = psi->write_buf(type, reason, id, part, psinfo->buf,
+ compressed, c, psi);
+ if (unlikely(ret < 0))
+ break;
+ i += c;
+ }
+ spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+ return unlikely(ret < 0) ? ret : size;
+}
+
/*
* platform specific persistent storage driver registers with
* us here. If pstore is already mounted, call the platform
@@ -645,6 +679,8 @@ int pstore_register(struct pstore_info *psi)
if (!psi->write)
psi->write = pstore_write_compat;
+ if (!psi->write_buf_user)
+ psi->write_buf_user = pstore_write_buf_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);