On 17/08/2021 08:39, Leonardo Bras wrote:
Code used to create a ddw property that was previously scattered in
enable_ddw() is now gathered in ddw_property_create(), which deals with
allocation and filling the property, letting it ready for
of_property_add(), which now occurs in sequence.

This created an opportunity to reorganize the second part of enable_ddw():

Without this patch enable_ddw() does, in order:
kzalloc() property & members, create_ddw(), fill ddwprop inside property,
ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
of_add_property(), and list_add().

With this patch enable_ddw() does, in order:
create_ddw(), ddw_property_create(), of_add_property(),
ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
and list_add().

This change requires of_remove_property() in case anything fails after
of_add_property(), but we get to do tce_setrange_multi_pSeriesLP_walk
in all memory, which looks the most expensive operation, only if
everything else succeeds.

Also, the error path got remove_ddw() replaced by a new helper
__remove_dma_window(), which only removes the new DDW with an rtas-call.
For this, a new helper clean_dma_window() was needed to clean anything
that could left if walk_system_ram_range() fails.

Signed-off-by: Leonardo Bras <leobra...@gmail.com>
Reviewed-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---


Thanks for fixing the error paths
Reviewed-by: Frederic Barrat <fbar...@linux.ibm.com>


  arch/powerpc/platforms/pseries/iommu.c | 129 ++++++++++++++++---------
  1 file changed, 84 insertions(+), 45 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c 
b/arch/powerpc/platforms/pseries/iommu.c
index b34b473bbdc1..00392582fe10 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -795,17 +795,10 @@ static int __init disable_ddw_setup(char *str)
early_param("disable_ddw", disable_ddw_setup); -static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
-                             struct property *win)
+static void clean_dma_window(struct device_node *np, struct 
dynamic_dma_window_prop *dwp)
  {
-       struct dynamic_dma_window_prop *dwp;
-       u64 liobn;
        int ret;
- dwp = win->value;
-       liobn = (u64)be32_to_cpu(dwp->liobn);
-
-       /* clear the whole window, note the arg is in kernel pages */
        ret = tce_clearrange_multi_pSeriesLP(0,
                1ULL << (be32_to_cpu(dwp->window_shift) - PAGE_SHIFT), dwp);
        if (ret)
@@ -814,18 +807,39 @@ static void remove_dma_window(struct device_node *np, u32 
*ddw_avail,
        else
                pr_debug("%pOF successfully cleared tces in window.\n",
                         np);
+}
+
+/*
+ * Call only if DMA window is clean.
+ */
+static void __remove_dma_window(struct device_node *np, u32 *ddw_avail, u64 
liobn)
+{
+       int ret;
ret = rtas_call(ddw_avail[DDW_REMOVE_PE_DMA_WIN], 1, 1, NULL, liobn);
        if (ret)
-               pr_warn("%pOF: failed to remove direct window: rtas returned "
+               pr_warn("%pOF: failed to remove DMA window: rtas returned "
                        "%d to ibm,remove-pe-dma-window(%x) %llx\n",
                        np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
        else
-               pr_debug("%pOF: successfully removed direct window: rtas returned 
"
+               pr_debug("%pOF: successfully removed DMA window: rtas returned "
                        "%d to ibm,remove-pe-dma-window(%x) %llx\n",
                        np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
  }
+static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
+                             struct property *win)
+{
+       struct dynamic_dma_window_prop *dwp;
+       u64 liobn;
+
+       dwp = win->value;
+       liobn = (u64)be32_to_cpu(dwp->liobn);
+
+       clean_dma_window(np, dwp);
+       __remove_dma_window(np, ddw_avail, liobn);
+}
+
  static void remove_ddw(struct device_node *np, bool remove_prop)
  {
        struct property *win;
@@ -1153,6 +1167,35 @@ static int iommu_get_page_shift(u32 query_page_size)
        return 0;
  }
+static struct property *ddw_property_create(const char *propname, u32 liobn, u64 dma_addr,
+                                           u32 page_shift, u32 window_shift)
+{
+       struct dynamic_dma_window_prop *ddwprop;
+       struct property *win64;
+
+       win64 = kzalloc(sizeof(*win64), GFP_KERNEL);
+       if (!win64)
+               return NULL;
+
+       win64->name = kstrdup(propname, GFP_KERNEL);
+       ddwprop = kzalloc(sizeof(*ddwprop), GFP_KERNEL);
+       win64->value = ddwprop;
+       win64->length = sizeof(*ddwprop);
+       if (!win64->name || !win64->value) {
+               kfree(win64->name);
+               kfree(win64->value);
+               kfree(win64);
+               return NULL;
+       }
+
+       ddwprop->liobn = cpu_to_be32(liobn);
+       ddwprop->dma_base = cpu_to_be64(dma_addr);
+       ddwprop->tce_shift = cpu_to_be32(page_shift);
+       ddwprop->window_shift = cpu_to_be32(window_shift);
+
+       return win64;
+}
+
  /*
   * If the PE supports dynamic dma windows, and there is space for a table
   * that can map all pages in a linear offset, then setup such a table,
@@ -1171,12 +1214,12 @@ static bool enable_ddw(struct pci_dev *dev, struct 
device_node *pdn)
        struct ddw_query_response query;
        struct ddw_create_response create;
        int page_shift;
+       u64 win_addr;
        struct device_node *dn;
        u32 ddw_avail[DDW_APPLICABLE_SIZE];
        struct direct_window *window;
        struct property *win64;
        bool ddw_enabled = false;
-       struct dynamic_dma_window_prop *ddwprop;
        struct failed_ddw_pdn *fpdn;
        bool default_win_removed = false;
        bool pmem_present;
@@ -1293,72 +1336,68 @@ static bool enable_ddw(struct pci_dev *dev, struct 
device_node *pdn)
                        1ULL << page_shift);
                goto out_failed;
        }
-       win64 = kzalloc(sizeof(struct property), GFP_KERNEL);
-       if (!win64) {
-               dev_info(&dev->dev,
-                       "couldn't allocate property for 64bit dma window\n");
-               goto out_failed;
-       }
-       win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL);
-       win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL);
-       win64->length = sizeof(*ddwprop);
-       if (!win64->name || !win64->value) {
-               dev_info(&dev->dev,
-                       "couldn't allocate property name and value\n");
-               goto out_free_prop;
-       }
ret = create_ddw(dev, ddw_avail, &create, page_shift, len);
        if (ret != 0)
-               goto out_free_prop;
-
-       ddwprop->liobn = cpu_to_be32(create.liobn);
-       ddwprop->dma_base = cpu_to_be64(((u64)create.addr_hi << 32) |
-                       create.addr_lo);
-       ddwprop->tce_shift = cpu_to_be32(page_shift);
-       ddwprop->window_shift = cpu_to_be32(len);
+               goto out_failed;
dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %pOF\n",
                  create.liobn, dn);
- window = ddw_list_new_entry(pdn, ddwprop);
+       win_addr = ((u64)create.addr_hi << 32) | create.addr_lo;
+       win64 = ddw_property_create(DIRECT64_PROPNAME, create.liobn, win_addr,
+                                   page_shift, len);
+       if (!win64) {
+               dev_info(&dev->dev,
+                        "couldn't allocate property, property name, or 
value\n");
+               goto out_remove_win;
+       }
+
+       ret = of_add_property(pdn, win64);
+       if (ret) {
+               dev_err(&dev->dev, "unable to add dma window property for %pOF: 
%d",
+                       pdn, ret);
+               goto out_free_prop;
+       }
+
+       window = ddw_list_new_entry(pdn, win64->value);
        if (!window)
-               goto out_clear_window;
+               goto out_del_prop;
ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
                        win64->value, tce_setrange_multi_pSeriesLP_walk);
        if (ret) {
                dev_info(&dev->dev, "failed to map direct window for %pOF: 
%d\n",
                         dn, ret);
-               goto out_free_window;
-       }
- ret = of_add_property(pdn, win64);
-       if (ret) {
-               dev_err(&dev->dev, "unable to add dma window property for %pOF: 
%d",
-                        pdn, ret);
-               goto out_free_window;
+               /* Make sure to clean DDW if any TCE was set*/
+               clean_dma_window(pdn, win64->value);
+               goto out_del_list;
        }
spin_lock(&direct_window_list_lock);
        list_add(&window->list, &direct_window_list);
        spin_unlock(&direct_window_list_lock);
- dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base);
+       dev->dev.archdata.dma_offset = win_addr;
        ddw_enabled = true;
        goto out_unlock;
-out_free_window:
+out_del_list:
        kfree(window);
-out_clear_window:
-       remove_ddw(pdn, true);
+out_del_prop:
+       of_remove_property(pdn, win64);
out_free_prop:
        kfree(win64->name);
        kfree(win64->value);
        kfree(win64);
+out_remove_win:
+       /* DDW is clean, so it's ok to call this directly. */
+       __remove_dma_window(pdn, ddw_avail, create.liobn);
+
  out_failed:
        if (default_win_removed)
                reset_dma_window(dev, pdn);

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