Module Name: src
Committed By: riastradh
Date: Tue Feb 21 11:40:13 UTC 2023
Modified Files:
src/sys/external/bsd/drm2/linux: linux_dma_buf.c
Log Message:
drm: Teach dmabuf to handle lseek.
Needed by libdrm_amdgpu.
Based on patch from Jeff Frasca -- thanks!
XXX pullup-10
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/external/bsd/drm2/linux/linux_dma_buf.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/linux/linux_dma_buf.c
diff -u src/sys/external/bsd/drm2/linux/linux_dma_buf.c:1.15 src/sys/external/bsd/drm2/linux/linux_dma_buf.c:1.16
--- src/sys/external/bsd/drm2/linux/linux_dma_buf.c:1.15 Sat Apr 9 23:44:44 2022
+++ src/sys/external/bsd/drm2/linux/linux_dma_buf.c Tue Feb 21 11:40:13 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_dma_buf.c,v 1.15 2022/04/09 23:44:44 riastradh Exp $ */
+/* $NetBSD: linux_dma_buf.c,v 1.16 2023/02/21 11:40:13 riastradh Exp $ */
/*-
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_dma_buf.c,v 1.15 2022/04/09 23:44:44 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_dma_buf.c,v 1.16 2023/02/21 11:40:13 riastradh Exp $");
#include <sys/types.h>
#include <sys/atomic.h>
@@ -48,6 +48,8 @@ static int dmabuf_fop_close(struct file
static int dmabuf_fop_kqfilter(struct file *, struct knote *);
static int dmabuf_fop_mmap(struct file *, off_t *, size_t, int, int *,
int *, struct uvm_object **, int *);
+static int dmabuf_fop_seek(struct file *fp, off_t delta, int whence,
+ off_t *newoffp, int flags);
static const struct fileops dmabuf_fileops = {
.fo_name = "dmabuf",
@@ -61,6 +63,7 @@ static const struct fileops dmabuf_fileo
.fo_kqfilter = dmabuf_fop_kqfilter,
.fo_restart = fnullop_restart,
.fo_mmap = dmabuf_fop_mmap,
+ .fo_seek = dmabuf_fop_seek,
};
struct dma_buf *
@@ -288,3 +291,54 @@ dmabuf_fop_mmap(struct file *file, off_t
return dmabuf->ops->mmap(dmabuf, offp, size, prot, flagsp, advicep,
uobjp, maxprotp);
}
+
+/*
+ * We don't actually do anything with the file offset; this is just how
+ * libdrm_amdgpu expects to find the size of the DMA buf. (Why it
+ * doesn't use fstat is unclear, but it doesn't really matter.)
+ */
+static int
+dmabuf_fop_seek(struct file *fp, off_t delta, int whence, off_t *newoffp,
+ int flags)
+{
+ const off_t OFF_MAX = __type_max(off_t);
+ struct dma_buf *dmabuf = fp->f_data;
+ off_t base, newoff;
+ int error;
+
+ mutex_enter(&fp->f_lock);
+
+ switch (whence) {
+ case SEEK_CUR:
+ base = fp->f_offset;
+ break;
+ case SEEK_END:
+ base = dmabuf->size;
+ break;
+ case SEEK_SET:
+ base = 0;
+ break;
+ default:
+ error = EINVAL;
+ goto out;
+ }
+
+ /* Check for arithmetic overflow and reject negative offsets. */
+ if (base < 0 || delta > OFF_MAX - base || base + delta < 0) {
+ error = EINVAL;
+ goto out;
+ }
+
+ /* Compute the new offset. */
+ newoff = base + delta;
+
+ /* Success! */
+ if (newoffp)
+ *newoffp = newoff;
+ if (flags & FOF_UPDATE_OFFSET)
+ fp->f_offset = newoff;
+ error = 0;
+
+out: mutex_exit(&fp->f_lock);
+ return error;
+}
