On 11/29/19 6:53 AM, Christophe Leroy wrote:

    CC      fs/io_uring.o
fs/io_uring.c: In function ‘loop_rw_iter’:
fs/io_uring.c:1628:21: error: implicit declaration of function ‘kmap’
[-Werror=implicit-function-declaration]
      iovec.iov_base = kmap(iter->bvec->bv_page)
                       ^
fs/io_uring.c:1628:19: warning: assignment makes pointer from integer
without a cast [-Wint-conversion]
      iovec.iov_base = kmap(iter->bvec->bv_page)
                     ^
fs/io_uring.c:1643:4: error: implicit declaration of function ‘kunmap’
[-Werror=implicit-function-declaration]
      kunmap(iter->bvec->bv_page);
      ^


Reverting commit 311ae9e159d8 ("io_uring: fix dead-hung for non-iter
fixed rw") clears the failure.

Most likely an #include is missing.

Huh weird how the build bots didn't catch that. Does the below work?

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2c2e8c25da01..745eb005fefe 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c

@@ -69,6 +69,7 @@
  #include <linux/nospec.h>
  #include <linux/sizes.h>
  #include <linux/hugetlb.h>
+#include <linux/highmem.h>
  
  #define CREATE_TRACE_POINTS
  #include <trace/events/io_uring.h>

-- 
Jens Axboe