system/ramblock: Rename @start -> @offset in ram_block_discard_range()

Rename @start as @offset, since it express an offset within a RAMBlock.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Peter Xu <peterx@redhat.com>
Message-Id: <20251002032812.26069-5-philmd@linaro.org>

2 files changed, 18 insertions, 16 deletions

diff --git a/include/system/ramblock.h b/include/system/ramblock.h
index 530c5a2e4c..85cceff6bc 100644
--- a/include/system/ramblock.h
+++ b/include/system/ramblock.h
@@ -103,8 +103,10 @@ struct RamBlockAttributes {
     QLIST_HEAD(, RamDiscardListener) rdl_list;
 };
 
-int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length);
-int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start,
+/* @offset: the offset within the RAMBlock */
+int ram_block_discard_range(RAMBlock *rb, uint64_t offset, size_t length);
+/* @offset: the offset within the RAMBlock */
+int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t offset,
                                         size_t length);
 
 RamBlockAttributes *ram_block_attributes_create(RAMBlock *ram_block);
diff --git a/system/physmem.c b/system/physmem.c
index cb3e5fcfdc..a37592fd32 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -3795,18 +3795,18 @@ int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque)
 }
 
 /*
- * Unmap pages of memory from start to start+length such that
+ * Unmap pages of memory from offset to offset+length such that
  * they a) read as 0, b) Trigger whatever fault mechanism
  * the OS provides for postcopy.
  * The pages must be unmapped by the end of the function.
  * Returns: 0 on success, none-0 on failure
  *
  */
-int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
+int ram_block_discard_range(RAMBlock *rb, uint64_t offset, size_t length)
 {
     int ret = -1;
 
-    uint8_t *host_startaddr = rb->host + start;
+    uint8_t *host_startaddr = rb->host + offset;
 
     if (!QEMU_PTR_IS_ALIGNED(host_startaddr, rb->page_size)) {
         error_report("%s: Unaligned start address: %p",
@@ -3814,7 +3814,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
         goto err;
     }
 
-    if ((start + length) <= rb->max_length) {
+    if ((offset + length) <= rb->max_length) {
         bool need_madvise, need_fallocate;
         if (!QEMU_IS_ALIGNED(length, rb->page_size)) {
             error_report("%s: Unaligned length: %zx", __func__, length);
@@ -3865,11 +3865,11 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
             }
 
             ret = fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
-                            start + rb->fd_offset, length);
+                            offset + rb->fd_offset, length);
             if (ret) {
                 ret = -errno;
                 error_report("%s: Failed to fallocate %s:%" PRIx64 "+%" PRIx64
-                             " +%zx (%d)", __func__, rb->idstr, start,
+                             " +%zx (%d)", __func__, rb->idstr, offset,
                              rb->fd_offset, length, ret);
                 goto err;
             }
@@ -3877,7 +3877,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
             ret = -ENOSYS;
             error_report("%s: fallocate not available/file"
                          "%s:%" PRIx64 "+%" PRIx64 " +%zx (%d)", __func__,
-                         rb->idstr, start, rb->fd_offset, length, ret);
+                         rb->idstr, offset, rb->fd_offset, length, ret);
             goto err;
 #endif
         }
@@ -3897,13 +3897,13 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
                 ret = -errno;
                 error_report("%s: Failed to discard range "
                              "%s:%" PRIx64 " +%zx (%d)",
-                             __func__, rb->idstr, start, length, ret);
+                             __func__, rb->idstr, offset, length, ret);
                 goto err;
             }
 #else
             ret = -ENOSYS;
             error_report("%s: MADVISE not available %s:%" PRIx64 " +%zx (%d)",
-                         __func__, rb->idstr, start, length, ret);
+                         __func__, rb->idstr, offset, length, ret);
             goto err;
 #endif
         }
@@ -3911,14 +3911,14 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
                                       need_madvise, need_fallocate, ret);
     } else {
         error_report("%s: Overrun block '%s' (%" PRIu64 "/%zx/" RAM_ADDR_FMT")",
-                     __func__, rb->idstr, start, length, rb->max_length);
+                     __func__, rb->idstr, offset, length, rb->max_length);
     }
 
 err:
     return ret;
 }
 
-int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start,
+int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t offset,
                                         size_t length)
 {
     int ret = -1;
@@ -3926,17 +3926,17 @@ int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start,
 #ifdef CONFIG_FALLOCATE_PUNCH_HOLE
     /* ignore fd_offset with guest_memfd */
     ret = fallocate(rb->guest_memfd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
-                    start, length);
+                    offset, length);
 
     if (ret) {
         ret = -errno;
         error_report("%s: Failed to fallocate %s:%" PRIx64 " +%zx (%d)",
-                     __func__, rb->idstr, start, length, ret);
+                     __func__, rb->idstr, offset, length, ret);
     }
 #else
     ret = -ENOSYS;
     error_report("%s: fallocate not available %s:%" PRIx64 " +%zx (%d)",
-                 __func__, rb->idstr, start, length, ret);
+                 __func__, rb->idstr, offset, length, ret);
 #endif
 
     return ret;