+int
+buf_shadow(buf_t bp)
+{
+ if (bp->b_lflags & BL_SHADOW)
+ return 1;
+ return 0;
+}
+
+
+buf_t
+buf_create_shadow_priv(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg)
+{
+ return (buf_create_shadow_internal(bp, force_copy, external_storage, iodone, arg, 1));
+}
+
+buf_t
+buf_create_shadow(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg)
+{
+ return (buf_create_shadow_internal(bp, force_copy, external_storage, iodone, arg, 0));
+}
+
+
+static buf_t
+buf_create_shadow_internal(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg, int priv)
+{
+ buf_t io_bp;
+
+ KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_START, bp, 0, 0, 0, 0);
+
+ if ( !(bp->b_flags & B_META) || (bp->b_lflags & BL_IOBUF)) {
+
+ KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_END, bp, 0, 0, 0, 0);
+ return (NULL);
+ }
+#ifdef BUF_MAKE_PRIVATE
+ if (bp->b_shadow_ref && bp->b_data_ref == 0 && external_storage == 0)
+ panic("buf_create_shadow: %p is in the private state (%d, %d)", bp, bp->b_shadow_ref, bp->b_data_ref);
+#endif
+ io_bp = alloc_io_buf(bp->b_vp, priv);
+
+ io_bp->b_flags = bp->b_flags & (B_META | B_ZALLOC | B_ASYNC | B_READ | B_FUA);
+ io_bp->b_blkno = bp->b_blkno;
+ io_bp->b_lblkno = bp->b_lblkno;
+
+ if (iodone) {
+ io_bp->b_transaction = arg;
+ io_bp->b_iodone = iodone;
+ io_bp->b_flags |= B_CALL;
+ }
+ if (force_copy == FALSE) {
+ io_bp->b_bcount = bp->b_bcount;
+ io_bp->b_bufsize = bp->b_bufsize;
+
+ if (external_storage) {
+ io_bp->b_datap = external_storage;
+#ifdef BUF_MAKE_PRIVATE
+ io_bp->b_data_store = NULL;
+#endif
+ } else {
+ io_bp->b_datap = bp->b_datap;
+#ifdef BUF_MAKE_PRIVATE
+ io_bp->b_data_store = bp;
+#endif
+ }
+ *(buf_t *)(&io_bp->b_orig) = bp;
+
+ lck_mtx_lock_spin(buf_mtxp);
+
+ io_bp->b_lflags |= BL_SHADOW;
+ io_bp->b_shadow = bp->b_shadow;
+ bp->b_shadow = io_bp;
+ bp->b_shadow_ref++;
+
+#ifdef BUF_MAKE_PRIVATE
+ if (external_storage)
+ io_bp->b_lflags |= BL_EXTERNAL;
+ else
+ bp->b_data_ref++;
+#endif
+ lck_mtx_unlock(buf_mtxp);
+ } else {
+ if (external_storage) {
+#ifdef BUF_MAKE_PRIVATE
+ io_bp->b_lflags |= BL_EXTERNAL;
+#endif
+ io_bp->b_bcount = bp->b_bcount;
+ io_bp->b_bufsize = bp->b_bufsize;
+ io_bp->b_datap = external_storage;
+ } else {
+ allocbuf(io_bp, bp->b_bcount);
+
+ io_bp->b_lflags |= BL_IOBUF_ALLOC;
+ }
+ bcopy((caddr_t)bp->b_datap, (caddr_t)io_bp->b_datap, bp->b_bcount);
+
+#ifdef BUF_MAKE_PRIVATE
+ io_bp->b_data_store = NULL;
+#endif
+ }
+ KERNEL_DEBUG(0xbbbbc000 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, io_bp, 0);
+
+ return (io_bp);
+}
+
+
+#ifdef BUF_MAKE_PRIVATE
+errno_t
+buf_make_private(buf_t bp)
+{
+ buf_t ds_bp;
+ buf_t t_bp;
+ struct buf my_buf;
+
+ KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_START, bp, bp->b_shadow_ref, 0, 0, 0);
+
+ if (bp->b_shadow_ref == 0 || bp->b_data_ref == 0 || ISSET(bp->b_lflags, BL_SHADOW)) {
+
+ KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, EINVAL, 0);
+ return (EINVAL);
+ }
+ my_buf.b_flags = B_META;
+ my_buf.b_datap = (uintptr_t)NULL;
+ allocbuf(&my_buf, bp->b_bcount);
+
+ bcopy((caddr_t)bp->b_datap, (caddr_t)my_buf.b_datap, bp->b_bcount);
+
+ lck_mtx_lock_spin(buf_mtxp);
+
+ for (t_bp = bp->b_shadow; t_bp; t_bp = t_bp->b_shadow) {
+ if ( !ISSET(bp->b_lflags, BL_EXTERNAL))
+ break;
+ }
+ ds_bp = t_bp;
+
+ if (ds_bp == NULL && bp->b_data_ref)
+ panic("buf_make_private: b_data_ref != 0 && ds_bp == NULL");
+
+ if (ds_bp && (bp->b_data_ref == 0 || bp->b_shadow_ref == 0))
+ panic("buf_make_private: ref_count == 0 && ds_bp != NULL");
+
+ if (ds_bp == NULL) {
+ lck_mtx_unlock(buf_mtxp);
+
+ buf_free_meta_store(&my_buf);
+
+ KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, EINVAL, 0);
+ return (EINVAL);
+ }
+ for (t_bp = bp->b_shadow; t_bp; t_bp = t_bp->b_shadow) {
+ if ( !ISSET(t_bp->b_lflags, BL_EXTERNAL))
+ t_bp->b_data_store = ds_bp;
+ }
+ ds_bp->b_data_ref = bp->b_data_ref;
+
+ bp->b_data_ref = 0;
+ bp->b_datap = my_buf.b_datap;
+
+ lck_mtx_unlock(buf_mtxp);
+
+ KERNEL_DEBUG(0xbbbbc004 | DBG_FUNC_END, bp, bp->b_shadow_ref, 0, 0, 0);
+ return (0);
+}
+#endif
+
projects / apple / xnu.git / blobdiff