[PATCH for_v22 3/6] x86/sgx: Move encl_page insertion into tree out of alloc flow

[Sean Christopherson <sean.j.christopherson@intel.com>]

Move insertion into the page tree out of sgx_encl_page_alloc() so that
the function can be moved out from under encl->lock.  This is a
preparatory step for removing the add page worker, as the encl_page is
needed to allocate its EPC page, and EPC page allocation must be done
without holding encl->lock so that it can trigger reclaim if necessary.

Note, radix_tree_insert() returns -EEXIST if the the slot is already in
use, i.e. there's no need to pre-check via radix_tree_lookup().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kernel/cpu/sgx/driver/ioctl.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
index 64deab36ed05..126f95afa9a1 100644
--- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
@@ -251,10 +251,7 @@ static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
 						 u64 page_type)
 {
 	struct sgx_encl_page *encl_page;
-	int ret;
 
-	if (radix_tree_lookup(&encl->page_tree, PFN_DOWN(addr)))
-		return ERR_PTR(-EEXIST);
 	encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
 	if (!encl_page)
 		return ERR_PTR(-ENOMEM);
@@ -263,12 +260,7 @@ static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
 		encl_page->desc |= SGX_ENCL_PAGE_TCS;
 	encl_page->encl = encl;
 	encl_page->vm_prot_bits = calc_vm_prot_bits(prot, 0);
-	ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
-				encl_page);
-	if (ret) {
-		kfree(encl_page);
-		return ERR_PTR(ret);
-	}
+
 	return encl_page;
 }
 
@@ -539,6 +531,11 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr,
 		goto err_out_shrink;
 	}
 
+	ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
+				encl_page);
+	if (ret)
+		goto err_out_free;
+
 	ret = __sgx_encl_add_page(encl, encl_page, data, secinfo, mrmask);
 	if (ret)
 		goto err_out;
@@ -549,6 +546,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr,
 err_out:
 	radix_tree_delete(&encl_page->encl->page_tree,
 			  PFN_DOWN(encl_page->desc));
+err_out_free:
 	kfree(encl_page);
 
 err_out_shrink:
-- 
2.22.0