| Message ID | 165973754730.1558392.15466392461645857658.stgit@dwillia2-xfh.jf.intel.com |
|---|---|
| State | Accepted |
| Commit | 1cd8a2537eb07751d405ab7e2223f20338a90506 |
| Headers | show |
| Series | cxl/hdm: Fix skip allocations vs multiple pmem allocations | expand |
On Fri, Aug 05, 2022 at 03:12:27PM -0700, Dan Williams wrote: > Vishal notes that when attempting to define a second pmem region on a > device the DPA allocation fails with a message of the form: > > decoder11.1: failed to reserve skipped space > > Recall that the skip setting is used when there is a pmem allocation in > the presence of free ram DPA space. The first pmem allocation skips over > the free ram and subsequent pmem allocations do not require a skip. The > bug is that a skip is still attempted and the DPA reservation code > flags the double skip allocation conflict. > > Fixes: cf880423b6a0 ("cxl/hdm: Add support for allocating DPA to an endpoint decoder") > Reported-by: Vishal Verma <vishal.l.verma@intel.com> > Tested-by: Vishal Verma <vishal.l.verma@intel.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> > --- > drivers/cxl/core/hdm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c > index e096f74e19df..d1d2caea5c62 100644 > --- a/drivers/cxl/core/hdm.c > +++ b/drivers/cxl/core/hdm.c > @@ -445,7 +445,16 @@ int cxl_dpa_alloc(struct cxl_endpoint_decoder *cxled, unsigned long long size) > start = free_pmem_start; > avail = cxlds->pmem_res.end - start + 1; > skip_start = free_ram_start; > - skip_end = start - 1; > + > + /* > + * If some pmem is already allocated, then that allocation > + * already handled the skip. > + */ > + if (cxlds->pmem_res.child && > + skip_start == cxlds->pmem_res.child->start) > + skip_end = skip_start - 1; > + else > + skip_end = start - 1; > skip = skip_end - skip_start + 1; > } else { > dev_dbg(dev, "mode not set\n"); >
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c index e096f74e19df..d1d2caea5c62 100644 --- a/drivers/cxl/core/hdm.c +++ b/drivers/cxl/core/hdm.c @@ -445,7 +445,16 @@ int cxl_dpa_alloc(struct cxl_endpoint_decoder *cxled, unsigned long long size) start = free_pmem_start; avail = cxlds->pmem_res.end - start + 1; skip_start = free_ram_start; - skip_end = start - 1; + + /* + * If some pmem is already allocated, then that allocation + * already handled the skip. + */ + if (cxlds->pmem_res.child && + skip_start == cxlds->pmem_res.child->start) + skip_end = skip_start - 1; + else + skip_end = start - 1; skip = skip_end - skip_start + 1; } else { dev_dbg(dev, "mode not set\n");
Vishal notes that when attempting to define a second pmem region on a device the DPA allocation fails with a message of the form: decoder11.1: failed to reserve skipped space Recall that the skip setting is used when there is a pmem allocation in the presence of free ram DPA space. The first pmem allocation skips over the free ram and subsequent pmem allocations do not require a skip. The bug is that a skip is still attempted and the DPA reservation code flags the double skip allocation conflict. Fixes: cf880423b6a0 ("cxl/hdm: Add support for allocating DPA to an endpoint decoder") Reported-by: Vishal Verma <vishal.l.verma@intel.com> Tested-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/cxl/core/hdm.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)