pstore/pmsg: drop bounce buffer

[mirror_ubuntu-bionic-kernel.git] / fs / pstore / platform.c

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 76dd604a0f2cc9ec3b19670357250ad21f95d40b..14984d902a99286ad19a27a906fa0ac2a7255613 100644 (file)
--- 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);