svm: fix shared hdr migration

Avoid changing the header on attach as it may be in use. Instead, as for
chunks, allocate header to be collected on detach.

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Ib316ecb5d61ae161032869b6f6a1863f1105a1d9

2 files changed, 9 insertions, 7 deletions

diff --git a/src/svm/fifo_segment.c b/src/svm/fifo_segment.c
index 9f1e46c9df6..5408567b8f4 100644
--- a/src/svm/fifo_segment.c
+++ b/src/svm/fifo_segment.c
@@ -969,7 +969,10 @@ fifo_segment_detach_fifo (fifo_segment_t *fs, svm_fifo_t **f)
   fsh_slice_collect_chunks (fs->h, fss, of->chunks_at_attach);
   of->chunks_at_attach = 0;
 
-  fss_fifo_free_list_push (fs->h, fss, of->shr);
+  /* Collect hdr that was provided in return for the detached */
+  fss_fifo_free_list_push (fs->h, fss, of->hdr_at_attach);
+  of->hdr_at_attach = 0;
+
   clib_mem_bulk_free (pfss->fifos, *f);
   *f = 0;
 }
@@ -992,21 +995,19 @@ fifo_segment_attach_fifo (fifo_segment_t *fs, svm_fifo_t **f, u32 slice_index)
   if (nf->flags & SVM_FIFO_F_LL_TRACKED)
     pfss_fifo_add_active_list (pfss, nf);
 
-  /* Update allocated chunks for fifo segment and build list of
-   * chunks to be freed, i.e, returned to old slice at detach */
+  /* Allocate shared hdr and chunks to be collected at detach in return
+   * for those that are being attached now */
   of = *f;
-  of->shr = fsh_try_alloc_fifo_hdr (fs->h, fss);
+  of->hdr_at_attach = fsh_try_alloc_fifo_hdr (fs->h, fss);
 
   c = fs_chunk_ptr (fs->h, nf->shr->start_chunk);
   of->chunks_at_attach = pc = fsh_try_alloc_chunk (fs->h, fss, c->length);
-  c = fs_chunk_ptr (fs->h, c->next);
 
-  while (c)
+  while ((c = fs_chunk_ptr (fs->h, c->next)))
     {
       nc = fsh_try_alloc_chunk (fs->h, fss, c->length);
       pc->next = fs_chunk_sptr (fs->h, nc);
       pc = nc;
-      c = fs_chunk_ptr (fs->h, c->next);
     }
 
   nf->shr->slice_index = slice_index;
diff --git a/src/svm/fifo_types.h b/src/svm/fifo_types.h
index a1b57748e09..670fd2aff1a 100644
--- a/src/svm/fifo_types.h
+++ b/src/svm/fifo_types.h
@@ -110,6 +110,7 @@ typedef struct _svm_fifo
   struct _svm_fifo *prev; /**< prev in active chain */
 
   svm_fifo_chunk_t *chunks_at_attach; /**< chunks to be accounted at detach */
+  svm_fifo_shared_t *hdr_at_attach;   /**< hdr to be freed at detach */
 
 #if SVM_FIFO_TRACE
   svm_fifo_trace_elem_t *trace;