From: Patrick Kelsey pat.kelsey@cornelisnetworks.com
[ Upstream commit a0d198f79a8d033bd46605b779859193649f1f99 ]
Fix arithmetic and logic errors in hfi1_can_pin_pages() that would allow hfi1 to attempt pinning pages in cases where it should not because of resource limits or lack of required capability.
Fixes: 2c97ce4f3c29 ("IB/hfi1: Add pin query function") Link: https://lore.kernel.org/r/167656658362.2223096.10954762619837718026.stgit@aw... Signed-off-by: Brendan Cunningham bcunningham@cornelisnetworks.com Signed-off-by: Patrick Kelsey pat.kelsey@cornelisnetworks.com Signed-off-by: Dennis Dalessandro dennis.dalessandro@cornelisnetworks.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/hw/hfi1/user_pages.c | 61 ++++++++++++++++--------- 1 file changed, 40 insertions(+), 21 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index 7bce963e2ae69..36aaedc651456 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/drivers/infiniband/hw/hfi1/user_pages.c @@ -29,33 +29,52 @@ MODULE_PARM_DESC(cache_size, "Send and receive side cache size limit (in MB)"); bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm, u32 nlocked, u32 npages) { - unsigned long ulimit = rlimit(RLIMIT_MEMLOCK), pinned, cache_limit, - size = (cache_size * (1UL << 20)); /* convert to bytes */ - unsigned int usr_ctxts = - dd->num_rcv_contexts - dd->first_dyn_alloc_ctxt; - bool can_lock = capable(CAP_IPC_LOCK); + unsigned long ulimit_pages; + unsigned long cache_limit_pages; + unsigned int usr_ctxts;
/* - * Calculate per-cache size. The calculation below uses only a quarter - * of the available per-context limit. This leaves space for other - * pinning. Should we worry about shared ctxts? + * Perform RLIMIT_MEMLOCK based checks unless CAP_IPC_LOCK is present. */ - cache_limit = (ulimit / usr_ctxts) / 4; - - /* If ulimit isn't set to "unlimited" and is smaller than cache_size. */ - if (ulimit != (-1UL) && size > cache_limit) - size = cache_limit; - - /* Convert to number of pages */ - size = DIV_ROUND_UP(size, PAGE_SIZE); - - pinned = atomic64_read(&mm->pinned_vm); + if (!capable(CAP_IPC_LOCK)) { + ulimit_pages = + DIV_ROUND_DOWN_ULL(rlimit(RLIMIT_MEMLOCK), PAGE_SIZE); + + /* + * Pinning these pages would exceed this process's locked memory + * limit. + */ + if (atomic64_read(&mm->pinned_vm) + npages > ulimit_pages) + return false; + + /* + * Only allow 1/4 of the user's RLIMIT_MEMLOCK to be used for HFI + * caches. This fraction is then equally distributed among all + * existing user contexts. Note that if RLIMIT_MEMLOCK is + * 'unlimited' (-1), the value of this limit will be > 2^42 pages + * (2^64 / 2^12 / 2^8 / 2^2). + * + * The effectiveness of this check may be reduced if I/O occurs on + * some user contexts before all user contexts are created. This + * check assumes that this process is the only one using this + * context (e.g., the corresponding fd was not passed to another + * process for concurrent access) as there is no per-context, + * per-process tracking of pinned pages. It also assumes that each + * user context has only one cache to limit. + */ + usr_ctxts = dd->num_rcv_contexts - dd->first_dyn_alloc_ctxt; + if (nlocked + npages > (ulimit_pages / usr_ctxts / 4)) + return false; + }
- /* First, check the absolute limit against all pinned pages. */ - if (pinned + npages >= ulimit && !can_lock) + /* + * Pinning these pages would exceed the size limit for this cache. + */ + cache_limit_pages = cache_size * (1024 * 1024) / PAGE_SIZE; + if (nlocked + npages > cache_limit_pages) return false;
- return ((nlocked + npages) <= size) || can_lock; + return true; }
int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t npages,