target: Have core_tmr_alloc_req() take an explicit GFP_xxx flag

Testing in_interrupt() to know when sleeping is allowed is not really
reliable (since eg it won't be true if the caller is holding a spinlock).
Instead have the caller tell core_tmr_alloc_req() what GFP_xxx to use;
every caller except tcm_qla2xxx can use GFP_KERNEL.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index d04cc10..efc5ec7 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -43,12 +43,12 @@
 struct se_tmr_req *core_tmr_alloc_req(
 	struct se_cmd *se_cmd,
 	void *fabric_tmr_ptr,
-	u8 function)
+	u8 function,
+	gfp_t gfp_flags)
 {
 	struct se_tmr_req *tmr;
 
-	tmr = kmem_cache_zalloc(se_tmr_req_cache, (in_interrupt()) ?
-					GFP_ATOMIC : GFP_KERNEL);
+	tmr = kmem_cache_zalloc(se_tmr_req_cache, gfp_flags);
 	if (!tmr) {
 		pr_err("Unable to allocate struct se_tmr_req\n");
 		return ERR_PTR(-ENOMEM);