IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules
Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.
Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.
This has a number of advantages:
- It is better design from the standpoint of making generic code a
library that can be used or overridden by device-specific code as
the details of specific devices dictate.
- Drivers that do not need to pin userspace memory regions do not
need to take the performance hit of calling ib_mem_get(). For
example, although I have not tried to implement it in this patch,
the ipath driver should be able to avoid pinning memory and just
use copy_{to,from}_user() to access userspace memory regions.
- Buffers that need special mapping treatment can be identified by
the low-level driver. For example, it may be possible to solve
some Altix-specific memory ordering issues with mthca CQs in
userspace by mapping CQ buffers with extra flags.
- Drivers that need to pin and DMA map userspace memory for things
other than memory regions can use ib_umem_get() directly, instead
of hacks using extra parameters to their reg_phys_mr method. For
example, the mlx4 driver that is pending being merged needs to pin
and DMA map QP and CQ buffers, but it does not need to create a
memory key for these buffers. So the cleanest solution is for mlx4
to call ib_umem_get() in the create_qp and create_cq methods.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/amso1100/c2_provider.c b/drivers/infiniband/hw/amso1100/c2_provider.c
index 1091662..997cf15 100644
--- a/drivers/infiniband/hw/amso1100/c2_provider.c
+++ b/drivers/infiniband/hw/amso1100/c2_provider.c
@@ -56,6 +56,7 @@
#include <asm/byteorder.h>
#include <rdma/ib_smi.h>
+#include <rdma/ib_umem.h>
#include <rdma/ib_user_verbs.h>
#include "c2.h"
#include "c2_provider.h"
@@ -396,6 +397,7 @@
}
mr->pd = to_c2pd(ib_pd);
+ mr->umem = NULL;
pr_debug("%s - page shift %d, pbl_depth %d, total_len %u, "
"*iova_start %llx, first pa %llx, last pa %llx\n",
__FUNCTION__, page_shift, pbl_depth, total_len,
@@ -428,8 +430,8 @@
return c2_reg_phys_mr(pd, &bl, 1, acc, &kva);
}
-static struct ib_mr *c2_reg_user_mr(struct ib_pd *pd, struct ib_umem *region,
- int acc, struct ib_udata *udata)
+static struct ib_mr *c2_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
+ u64 virt, int acc, struct ib_udata *udata)
{
u64 *pages;
u64 kva = 0;
@@ -441,15 +443,23 @@
struct c2_mr *c2mr;
pr_debug("%s:%u\n", __FUNCTION__, __LINE__);
- shift = ffs(region->page_size) - 1;
c2mr = kmalloc(sizeof(*c2mr), GFP_KERNEL);
if (!c2mr)
return ERR_PTR(-ENOMEM);
c2mr->pd = c2pd;
+ c2mr->umem = ib_umem_get(pd->uobject->context, start, length, acc);
+ if (IS_ERR(c2mr->umem)) {
+ err = PTR_ERR(c2mr->umem);
+ kfree(c2mr);
+ return ERR_PTR(err);
+ }
+
+ shift = ffs(c2mr->umem->page_size) - 1;
+
n = 0;
- list_for_each_entry(chunk, ®ion->chunk_list, list)
+ list_for_each_entry(chunk, &c2mr->umem->chunk_list, list)
n += chunk->nents;
pages = kmalloc(n * sizeof(u64), GFP_KERNEL);
@@ -459,35 +469,34 @@
}
i = 0;
- list_for_each_entry(chunk, ®ion->chunk_list, list) {
+ list_for_each_entry(chunk, &c2mr->umem->chunk_list, list) {
for (j = 0; j < chunk->nmap; ++j) {
len = sg_dma_len(&chunk->page_list[j]) >> shift;
for (k = 0; k < len; ++k) {
pages[i++] =
sg_dma_address(&chunk->page_list[j]) +
- (region->page_size * k);
+ (c2mr->umem->page_size * k);
}
}
}
- kva = (u64)region->virt_base;
+ kva = virt;
err = c2_nsmr_register_phys_kern(to_c2dev(pd->device),
pages,
- region->page_size,
+ c2mr->umem->page_size,
i,
- region->length,
- region->offset,
+ length,
+ c2mr->umem->offset,
&kva,
c2_convert_access(acc),
c2mr);
kfree(pages);
- if (err) {
- kfree(c2mr);
- return ERR_PTR(err);
- }
+ if (err)
+ goto err;
return &c2mr->ibmr;
err:
+ ib_umem_release(c2mr->umem);
kfree(c2mr);
return ERR_PTR(err);
}
@@ -502,8 +511,11 @@
err = c2_stag_dealloc(to_c2dev(ib_mr->device), ib_mr->lkey);
if (err)
pr_debug("c2_stag_dealloc failed: %d\n", err);
- else
+ else {
+ if (mr->umem)
+ ib_umem_release(mr->umem);
kfree(mr);
+ }
return err;
}