ublk: refactor common helper ublk_shmem_remove_ranges()

Extract the shared walk+erase+unpin+kfree loop into
ublk_shmem_remove_ranges(). When buf_index >= 0, only ranges matching
that index are removed; when buf_index < 0, all ranges are removed.

Also extract ublk_unpin_range_pages() to share the page unpinning
loop.

Convert both __ublk_ctrl_unreg_buf() and ublk_buf_cleanup() to use
the new helper.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Link: https://patch.msgid.link/20260423033058.2805135-3-tom.leiming@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index d5bbade15e653042ceb4cc3dd115267346526ddf..dfdb58d73e81e26803487104eb783607a288148b 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -5421,18 +5421,40 @@ err_free_pages:
        return ret;
 }
 
-static int __ublk_ctrl_unreg_buf(struct ublk_device *ub, int buf_index)
+static void ublk_unpin_range_pages(unsigned long base_pfn,
+                                  unsigned long nr_pages)
+{
+#define UBLK_UNPIN_BATCH       32
+       struct page *pages[UBLK_UNPIN_BATCH];
+       unsigned long off;
+
+       for (off = 0; off < nr_pages; ) {
+               unsigned int batch = min_t(unsigned long,
+                                          nr_pages - off, UBLK_UNPIN_BATCH);
+               unsigned int j;
+
+               for (j = 0; j < batch; j++)
+                       pages[j] = pfn_to_page(base_pfn + off + j);
+               unpin_user_pages(pages, batch);
+               off += batch;
+       }
+}
+
+/*
+ * Remove ranges from the maple tree matching buf_index, unpin pages
+ * and free range structs. If buf_index < 0, remove all ranges.
+ */
+static int ublk_shmem_remove_ranges(struct ublk_device *ub, int buf_index)
 {
        MA_STATE(mas, &ub->buf_tree, 0, ULONG_MAX);
        struct ublk_buf_range *range;
-       struct page *pages[32];
        int ret = -ENOENT;
 
        mas_lock(&mas);
        mas_for_each(&mas, range, ULONG_MAX) {
-               unsigned long base, nr, off;
+               unsigned long base, nr;
 
-               if (range->buf_index != buf_index)
+               if (buf_index >= 0 && range->buf_index != buf_index)
                        continue;
 
                ret = 0;
@@ -5440,16 +5462,7 @@ static int __ublk_ctrl_unreg_buf(struct ublk_device *ub, int buf_index)
                nr = mas.last - base + 1;
                mas_erase(&mas);
 
-               for (off = 0; off < nr; ) {
-                       unsigned int batch = min_t(unsigned long,
-                                                  nr - off, 32);
-                       unsigned int j;
-
-                       for (j = 0; j < batch; j++)
-                               pages[j] = pfn_to_page(base + off + j);
-                       unpin_user_pages(pages, batch);
-                       off += batch;
-               }
+               ublk_unpin_range_pages(base, nr);
                kfree(range);
        }
        mas_unlock(&mas);
@@ -5472,7 +5485,7 @@ static int ublk_ctrl_unreg_buf(struct ublk_device *ub,
 
        memflags = ublk_lock_buf_tree(ub);
 
-       ret = __ublk_ctrl_unreg_buf(ub, index);
+       ret = ublk_shmem_remove_ranges(ub, index);
        if (!ret)
                ida_free(&ub->buf_ida, index);
 
@@ -5482,31 +5495,7 @@ static int ublk_ctrl_unreg_buf(struct ublk_device *ub,
 
 static void ublk_buf_cleanup(struct ublk_device *ub)
 {
-       MA_STATE(mas, &ub->buf_tree, 0, ULONG_MAX);
-       struct ublk_buf_range *range;
-       struct page *pages[32];
-
-       mas_lock(&mas);
-       mas_for_each(&mas, range, ULONG_MAX) {
-               unsigned long base = mas.index;
-               unsigned long nr = mas.last - base + 1;
-               unsigned long off;
-
-               mas_erase(&mas);
-
-               for (off = 0; off < nr; ) {
-                       unsigned int batch = min_t(unsigned long,
-                                                  nr - off, 32);
-                       unsigned int j;
-
-                       for (j = 0; j < batch; j++)
-                               pages[j] = pfn_to_page(base + off + j);
-                       unpin_user_pages(pages, batch);
-                       off += batch;
-               }
-               kfree(range);
-       }
-       mas_unlock(&mas);
+       ublk_shmem_remove_ranges(ub, -1);
        mtree_destroy(&ub->buf_tree);
        ida_destroy(&ub->buf_ida);
 }